MLAB Mesa Laboratories Inc

Stockholder Rights Plans

If any shares of our common stock are to be issued upon conversion of any note and, at the time of such conversion, we have in effect any stockholder rights plan, then the holder of that note will be entitled to receive, in addition to, and concurrently with the delivery of, the consideration otherwise due upon such conversion, the rights set forth in such stockholder rights plan, unless such rights have separated from our common stock at such time, in which case, and only in such case, the conversion rate will be adjusted pursuant to the provisions described above in paragraph (3)(a) under the caption "— Conversion Rate Adjustments — Generally" on account of such separation as if, at the time of such separation, we had made a distribution of the type referred to in such paragraph to all holders of our common stock, subject to readjustment as described above if such rights expire, terminate or are redeemed. We currently do not have a stockholder rights plan.

Increase in Conversion Rate in Connection with a Make-Whole Fundamental Change

Generally

If a make-whole fundamental change occurs and the conversion date for the conversion of a note occurs during the related "make-whole fundamental change conversion period" (as defined below under the caption "— Definitions"), then, subject to the provisions described below, the conversion rate applicable to such conversion will be increased by a number of shares (the "additional shares") set forth in the table below corresponding (after interpolation as described below) to the effective date and the "stock price" (as defined below under the caption "— Definitions") of such make-whole fundamental change:

If such effective date or stock price is not set forth in the table above, then:

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if such stock price is between two stock prices in the table above or the effective date is between two dates in the table above, then the number of additional shares will be determined by a straight-line interpolation between the numbers of additional shares set forth for the higher and lower stock prices in the table and the earlier and later dates in the table above, as applicable, based on a 365- or 366-day year, as applicable; and

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§

if the stock price is greater than $          (subject to adjustment in the same manner as the stock prices set forth in the column headings of the table above are adjusted, as described below under the caption "— Adjustment of Stock Prices and Number of Additional Shares"), or less than $          (subject to adjustment in the same manner), per share, then no additional shares will be added to the conversion rate.

Notwithstanding anything to the contrary, in no event will the conversion rate be increased to an amount that exceeds               shares of our common stock per $1,000 principal amount of notes, which amount is subject to adjustment in the same manner as, and at the same time and for the same events for which, the conversion rate is required to be adjusted pursuant to the provisions described above under the caption "— Conversion Rate Adjustments — Generally."

Adjustment of Stock Prices and Number of Additional Shares

The stock prices in the first row ( i.e. , the column headers) of the table above will be adjusted in the same manner as, and at the same time and for the same events for which, the conversion price is adjusted as a result of the operation of the provisions described above under the caption "— Conversion Rate Adjustments — Generally." The numbers of additional shares in the table above will be adjusted in the same manner as, and at the same time and for the same events for which, the conversion rate is adjusted pursuant to the provisions described above under the caption "— Conversion Rate Adjustments — Generally."

Notice of Make-Whole Fundamental Change

We will notify noteholders of each make-whole fundamental change in accordance with the provisions described above under the caption "— When the Notes May Be Converted — Conversion upon Specified Corporate Events — Certain Corporate Events" (or, if the effective date of such make-whole fundamental change is on or after April 15, 2025, no later than such effective date).

Enforceability

Our obligation to increase the conversion rate as described above in connection with a make-whole fundamental change could be considered a penalty, in which case its enforceability would be subject to general principles of reasonableness and equitable remedies.

Effect of Common Stock Change Event

Generally

If there occurs any:

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recapitalization, reclassification or change of our common stock, other than (x) changes solely resulting from a subdivision or combination of our common stock, (y) a change only in par value or from par value to no par value or no par value to par value or (z) stock splits and stock combinations that do not involve the issuance of any other series or class of securities;



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consolidation, merger, combination or statutory share exchange involving us; or



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sale, lease or other transfer of all or substantially all of the assets of us and our subsidiaries, taken as a whole, to any person,

and, as a result of which, our common stock is converted into, or is exchanged for, or represents solely the right to receive, other securities, cash or other property, or any combination of the foregoing (such an event, a "common stock change event," and such other securities, cash or property, the "reference property," and the amount and kind of reference property that a holder of one share of our common stock would be entitled to receive on account of such common stock change event (without giving effect to any arrangement not to issue or deliver a fractional portion of any security or other property), a "reference property unit"), then, notwithstanding anything to the contrary,

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from and after the effective time of such common stock change event, (i) the consideration due upon conversion of any note, and the conditions to any such conversion, will be determined in the same manner as if each reference to any number of shares of common stock in the provisions described

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under this "— Conversion Rights" section (or in any related definitions) were instead a reference to the same number of reference property units; and (ii) for purposes of the definition of "fundamental change" and "make-whole fundamental change," the terms "common stock" and "common equity" will be deemed to mean the common equity, if any, forming part of such reference property;

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if such reference property unit consists entirely of cash, then we will be deemed to elect physical settlement in respect of all conversions whose conversion date occurs on or after the effective date of such common stock change event and will pay the cash due upon such conversions no later than the fifth business day after the relevant conversion date; and



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for these purposes, (i) the daily VWAP of any reference property unit or portion thereof that consists of a class of common equity securities will be determined by reference to the definition of "daily VWAP," substituting, if applicable, the Bloomberg page for such class of securities in such definition; and (ii) the daily VWAP of any reference property unit or portion thereof that does not consist of a class of common equity securities, and the last reported sale price of any reference property unit or portion thereof that does not consist of a class of securities, will be the fair value of such reference property unit or portion thereof, as applicable, determined in good faith by us (or, in the case of cash denominated in U.S. dollars, the face amount thereof).

If the reference property consists of more than a single type of consideration to be determined based in part upon any form of stockholder election, then the composition of the reference property unit will be deemed to be the weighted average of the types and amounts of consideration actually received, per share of our common stock, by the holders of our common stock. We will notify the noteholders of such weighted average as soon as practicable after such determination is made.

We will not become a party to any common stock change event unless its terms are consistent with the provisions described under this "— Effect of Common Stock Change Event" caption.

Execution of Supplemental Indenture

At or before the effective time of the common stock change event, we and the resulting, surviving or transferee person (if not us) of such common stock change event (the "successor person") will execute and deliver to the trustee a supplemental indenture that (i) provides for subsequent adjustments to the conversion rate in a manner consistent with the provisions described above (including giving effect, in our reasonable discretion, to the dividend threshold in a manner that preserves the economic interests of the noteholders); and (ii) contains such other provisions as we reasonably determine are appropriate to preserve the economic interests of the holders and to give effect to the provisions described above. If the reference property includes shares of stock or other securities or assets of a person other than the successor person, then such other person will also execute such supplemental indenture and such supplemental indenture will contain such additional provisions we reasonably determine are appropriate to preserve the economic interests of noteholders.

Notice of Common Stock Change Event

We will provide notice of each common stock change event to noteholders no later than the effective date of the common stock change event.

Exchange in Lieu of Conversion

Notwithstanding anything to the contrary, and subject to the terms of the indenture, if a note is submitted for conversion, we may elect to arrange to have such note exchanged in lieu of conversion by a financial institution we designate. To make such election, we must send notice of such election to the holder of such note before the close of business on the business day immediately following the conversion date for such note, and we must arrange for the financial institution to deliver the consideration due upon such conversion in the same manner and at the same time as we would have been required to do so. We will remain responsible to deliver such consideration if the financial institution fails to timely deliver the same.

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Equitable Adjustments to Prices

Whenever the indenture requires us to calculate the average of the last reported sale prices, or any function thereof, over a period of multiple days (including to calculate the stock price or an adjustment to the conversion rate), or to calculate daily VWAPs over an observation period, we will make proportionate adjustments to those calculations to account for any adjustment to the conversion rate pursuant to paragraph (1) above under the caption "— Conversion Rights — Conversion Rate Adjustments — Generally" that becomes effective, or any event requiring such an adjustment to the conversion rate where the ex-dividend date or effective date, as applicable, of such event occurs, at any time during such period or observation period, as applicable.

Fundamental Change Permits Noteholders to Require Us to Repurchase Notes

Generally

If a "fundamental change" (as defined below under the caption "— Definitions") occurs, then each noteholder will have the right (the "fundamental change repurchase right") to require us to repurchase its notes (or any portion thereof in an authorized denomination) for cash on a date (the "fundamental change repurchase date") of our choosing, which must be a business day that is no more than 35, nor less than 20, business days after the date we send the related fundamental change notice, as described below.

The repurchase price (the "fundamental change repurchase price") for a note tendered for repurchase will be the principal amount of such note plus accrued and unpaid interest on such note to, but excluding, the fundamental change repurchase date. However, if the fundamental change repurchase date is after a regular record date and on or before the next interest payment date, then (i) the holder of such note at the close of business on such regular record date will be entitled, notwithstanding such repurchase, to receive, on or, at our election, before such interest payment date, the unpaid interest that would have accrued on such note to, but excluding, such interest payment date; and (ii) the fundamental change repurchase price will not include accrued and unpaid interest on such note to, but excluding, the fundamental change repurchase date.

Notwithstanding anything to the contrary above, we may not repurchase any notes if the principal amount of the notes has been accelerated and such acceleration has not been rescinded on or before the fundamental change repurchase date (including as a result of the payment of the related fundamental change repurchase price and any related interest described above on the fundamental change repurchase date).

Notice of Fundamental Change

On or before the 20th calendar day after the occurrence of a fundamental change, we will send to each noteholder notice of such fundamental change containing certain information set forth in the indenture, including the fundamental change repurchase date, the fundamental change repurchase price and the procedures noteholders must follow to tender their notes for repurchase. Substantially contemporaneously, we will issue a press release through such national newswire service as we then use (or publish the same through such other widely disseminated public medium as we then use, including our website) containing the information set forth in the fundamental change notice.

Procedures to Exercise the Fundamental Change Repurchase Right

To exercise its fundamental change repurchase right with respect to a note, the holder thereof must deliver a notice (a "fundamental change repurchase notice") to the paying agent before the close of business on the business day immediately before the related fundamental change repurchase date (or such later time as may be required by law).

The fundamental change repurchase notice must contain certain information set forth in the indenture, including the certificate number of any physical notes to be repurchased, or must otherwise comply with the depositary procedures in the case of a global note.

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A noteholder that has delivered a fundamental change repurchase notice with respect to a note may withdraw that notice by delivering a withdrawal notice to the paying agent at any time before the close of business on the business day immediately before the fundamental change repurchase date. The withdrawal notice must contain certain information set forth in the indenture, including the certificate number of any physical notes with respect to which the withdrawal notice is being delivered, or must otherwise comply with the depositary procedures in the case of a global note.

Notes to be repurchased must be delivered to the paying agent (in the case of certificated notes) or the depositary procedures must be complied with (in the case of global notes) for the holder of those notes to be entitled to receive the fundamental change repurchase price.

Compliance with Securities Laws

We will comply, in all material respects, with all federal and state securities laws in connection with a repurchase following a fundamental change (including complying with Rules 13e-4 and 14e-1 under the Exchange Act and filing any required Schedule TO, to the extent applicable) so as to permit effecting such repurchase in the manner described above. However, to the extent that our obligations to offer to repurchase and to repurchase notes pursuant to the provisions described above conflict with any law or regulation that is applicable to us and enacted after the date we initially issue the notes, our compliance with such law or regulation will not be considered to be a default of those obligations.

Repurchase by Third Party

Notwithstanding anything to the contrary, we will be deemed to satisfy our obligations to repurchase notes pursuant to the provisions described above if (i) one or more third parties conduct the repurchase offer and repurchase tendered notes in a manner that would have satisfied our obligations to do the same if conducted directly by us; and (ii) an owner of a beneficial interest in any note repurchased by such third party or parties will not receive a lesser amount (as a result of taxes, additional expenses or for any other reason) than such owner would have received had we repurchased such note.

Consolidation, Merger and Asset Sale

For purposes of the notes, the description below under this section titled "— Consolidation, Merger and Asset Sale" supersedes, in its entirety, the information in the accompanying prospectus under the caption "Description of Debt Securities — Limitations on Merger and Other Transactions."

We will not consolidate with or merge with or into, or (directly, or indirectly through one or more of our subsidiaries) sell, lease or otherwise transfer, in one transaction or a series of transactions, all or substantially all of the assets of us and our subsidiaries, taken as a whole, to another person (a "business combination event"), unless:

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the resulting, surviving or transferee person is us or, if not us, is a corporation (the "successor corporation") duly organized and existing under the laws of the United States of America, any State thereof or the District of Columbia that expressly assumes (by executing and delivering to the trustee, at or before the effective time of such business combination event, a supplemental indenture) all of our obligations under the indenture and the notes; and



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immediately after giving effect to such business combination event, no default or event of default will have occurred and be continuing.

At the effective time of a business combination event that complies with the provisions described above, the successor corporation (if not us) will succeed to, and may exercise every right and power of, us under the indenture and the notes, and, except in the case of a lease, the predecessor company will be discharged from its obligations under the indenture and the notes.

The definition of "business combination event" includes a reference to "all or substantially all" of our and our subsidiaries' assets. There is no precise, established definition of the phrase "all or substantially all"

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under applicable law. Accordingly, there may be uncertainty as to whether the provisions described above would apply to a sale, lease or transfer of less than all of our and our subsidiaries' assets.

Events of Default

For purposes of the notes, the description below under this section titled "— Events of Default" supersedes, in its entirety, the information in the accompanying prospectus under the caption "Description of Debt Securities — Events of Default."

Generally

An "event of default" means the occurrence of any of the following:

(1)

a default in the payment when due (whether at maturity, upon repurchase upon fundamental change or otherwise) of the principal of, or the fundamental change repurchase price for, any note;

(2)

a default for 30 days in the payment when due of interest on any note;

(3)

our failure to deliver, when required by the indenture, a fundamental change notice or a notice pursuant to the provisions described above under the caption "— Conversion Rights — When the Notes May Be Converted — Conversion upon Specified Corporate Events" and, in the case of a fundamental change notice or a notice pursuant to the provisions described above under the caption "— Conversion Rights — When the Notes May Be Converted — Conversion upon Specified Corporate Events — Certain Corporate Events," such failure continues for a period of three business days;

(4)

a default in our obligation to convert a note in accordance with the indenture upon the exercise of the conversion right with respect thereto, and such failure continues for a period of three business days;

(5)

a default in our obligations described above under the caption "— Consolidation, Merger and Asset Sale";

(6)

a default in any of our obligations or agreements under the indenture or the notes (other than a default set forth in paragraphs (1), (2), (3), (4) or (5) above) where such default is not cured or waived within 60 days after notice to us by the trustee, or to us and the trustee by holders of at least 25% of the aggregate principal amount of notes then outstanding, which notice must specify such default, demand that it be remedied and state that such notice is a "notice of default";

(7)

a default by us or any of our "significant subsidiaries" (as defined below under the caption "— Definitions") with respect to any one or more mortgages, agreements or other instruments under which there is outstanding, or by which there is secured or evidenced, any indebtedness for money borrowed of at least $25,000,000 (or its foreign currency equivalent) in the aggregate of us or any of our significant subsidiaries, whether such indebtedness exists as of the date we first issue the notes or is thereafter created, where such default:

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constitutes a failure to pay the principal of such indebtedness when due and payable at its stated maturity, upon required repurchase, upon declaration of acceleration or otherwise, in each case after the expiration of any applicable grace period; or

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results in such indebtedness becoming or being declared due and payable before its stated maturity,

in each case where such default is not cured or waived within 30 days after notice to us by the trustee or to us and the trustee by holders of at least 25% of the aggregate principal amount of notes then outstanding;

(8)

one or more final judgments being rendered against us or any of our significant subsidiaries for the payment of at least $25,000,000 (or its foreign currency equivalent) in the aggregate (excluding any amounts covered by insurance), where such judgment is not discharged or stayed within 60 days after

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(i) the date on which the right to appeal the same has expired, if no such appeal has commenced; or (ii) the date on which all rights to appeal have been extinguished; and

(9)

certain events of bankruptcy, insolvency and reorganization with respect to us or any of our significant subsidiaries.

Acceleration

If an event of default described in paragraph (9) above occurs with respect to us (and not solely with respect to a significant subsidiary of ours), then the principal amount of, and all accrued and unpaid interest on, all of the notes then outstanding will immediately become due and payable without any further action or notice by any person. If an event of default (other than an event of default described in paragraph (9) above with respect to us and not solely with respect to a significant subsidiary of ours) occurs and is continuing, then, except as described below under the caption "— Special Interest as Sole Remedy for Certain Reporting Defaults," the trustee, by notice to us, or noteholders of at least 25% of the aggregate principal amount of notes then outstanding, by notice to us and the trustee, may declare the principal amount of, and all accrued and unpaid interest on, all of the notes then outstanding to become due and payable immediately.

Noteholders of a majority in aggregate principal amount of the notes then outstanding, by notice to us and the trustee, may, on behalf of all noteholders, rescind any acceleration of the notes and its consequences if (i) such rescission would not conflict with any judgment or decree of a court of competent jurisdiction; and (ii) all existing events of default (except the non-payment of principal of, or interest on, the notes that has become due solely because of such acceleration) have been cured or waived. No such rescission will affect any subsequent default or impair any right consequent thereto.

If any portion of the amount payable on the notes upon acceleration is considered by a court to be unearned interest (through the allocation of the value of the instrument to the embedded warrant or otherwise), then the court could disallow recovery of any such portion.

Waiver of Past Defaults

An event of default pursuant to paragraph (1), (2), (4) or (6) above (that, in the case of paragraph (6) only, results from a default under any covenant that cannot be amended without the consent of each affected noteholder), and a default that could lead to such an event of default, can be waived only with the consent of each affected noteholder. Each other default or event of default may be waived, on behalf of all noteholders, by noteholders of a majority in aggregate principal amount of the notes then outstanding.

Notice of Defaults

If a default or event of default occurs, then, within 30 days, we will notify the trustee, setting forth what action we are taking or propose to take with respect thereto; provided , however , that we are not required to deliver such notice if such default or event of default, as applicable, has been cured within the applicable grace period, if any, provided in the indenture. We must also provide the trustee annually with a certificate as to whether any defaults or events of default have occurred or are continuing. If a default or event of default occurs and is continuing and is known to the trustee, then the trustee must notify the noteholders of the same within 90 days after it occurs or, if it is not known to the trustee at such time, promptly (and in any event within 10 business days) after it becomes known to a responsible officer of the trustee. However, except in the case of a default or event of default in the payment of the principal of, or interest on, any note, the trustee may withhold such notice if and for so long as it in good faith determines that withholding such notice is in the interests of the noteholders.

Limitation on Suits; Absolute Rights of Noteholders

Except with respect to the rights referred to below, no noteholder may pursue any remedy with respect to the indenture or the notes, unless:

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such noteholder has previously delivered to the trustee notice that an event of default is continuing;

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noteholders of at least 25% in aggregate principal amount of the notes then outstanding deliver a written request to the trustee to pursue such remedy;



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such noteholder(s) offer and, if requested, provide to the trustee security and indemnity satisfactory to the trustee against any loss, liability or expense to the trustee that may result from the trustee's following such request;



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the trustee does not comply with such request within 60 calendar days after its receipt of such request and such offer of security or indemnity; and



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during such 60 calendar day period, noteholders of a majority in aggregate principal amount of the notes then outstanding do not deliver to the trustee a direction that is inconsistent with such request.

However, notwithstanding anything to the contrary, but without limiting the provisions described in the third paragraph under the caption "— Modification and Amendment," the right of each holder of a note to receive payment or delivery, as applicable, of the principal of, or the fundamental change repurchase price for, or any interest on, or the consideration due upon conversion of, such note on or after the respective due dates therefor, or to bring suit for the enforcement of any such payment or delivery on or after such respective due dates, will not be impaired or affected without the consent of such holder.

Noteholders of a majority in aggregate principal amount of the notes then outstanding may direct the time, method and place of conducting any proceeding for exercising any remedy available to the trustee or exercising any trust or power conferred on it. However, the trustee may refuse to follow any direction that conflicts with law, the indenture or the notes, or that, subject to the terms of the indenture, the trustee determines may be unduly prejudicial to the rights of other noteholders or may involve the trustee in liability, unless the trustee is offered security and indemnity satisfactory to the trustee against any loss, liability or expense to the trustee that may result from the trustee's following such direction.

Default Interest

Payments of any amounts due on the notes that are not made when due will accrue interest at a rate per annum equal to the stated interest on the notes.

Special Interest as Sole Remedy for Certain Reporting Defaults

Notwithstanding anything to the contrary described above, we may elect that the sole remedy for any event of default (a "reporting event of default") pursuant to paragraph (6) above arising from our failure to comply with our obligations described below under the caption "— Exchange Act Reports" (including our obligations under Section 314(a)(1) of the Trust Indenture Act) will, for each of the first 180 calendar days on which a reporting event of default has occurred and is continuing, consist exclusively of the accrual of special interest on the notes. If we have made such an election, then (i) the notes will be subject to acceleration as described above on account of the relevant reporting event of default from, and including, the 181st calendar day on which a reporting event of default has occurred and is continuing or if we fail to pay any accrued and unpaid special interest when due; and (ii) special interest will cease to accrue on any notes from, and including, such 181st calendar day.

Any special interest that accrues on a note will be payable on the same dates and in the same manner as the stated interest on such note and will accrue at a rate per annum equal to 0.25% of the principal amount thereof for the first 90 days on which special interest accrues and, thereafter, at a rate per annum equal to 0.50% of the principal amount thereof. For the avoidance of doubt, any special interest that accrues on a note will be in addition to the stated interest that accrues on such note.

To make the election to pay special interest as described above, we must provide notice of such election to noteholders before the date on which each reporting event of default first occurs. The notice will also, among other things, briefly describe the periods during which and rate at which special interest will accrue and the circumstances under which the notes will be subject to acceleration on account of such reporting event of default.

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Modification and Amendment

For purposes of the notes, the description below under this section titled "— Modification and Amendment" supersedes, in its entirety, the information in the accompanying prospectus under the caption "Description of Debt Securities — Modification and Waiver."

We and the trustee may, with the consent of holders of a majority in aggregate principal amount of the notes then outstanding, amend or supplement the indenture or the notes or waive compliance with any provision of the indenture or the notes. However, without the consent of each affected noteholder, no amendment or supplement to the indenture or the notes, or waiver of any provision of the indenture or the notes, may:

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reduce the principal, or extend the stated maturity, of any note;



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reduce the fundamental change repurchase price for any note or change the times at which, or the circumstances under which, the notes will be repurchased by us;



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reduce the rate, or extend the time for the payment, of interest on any note;



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make any change that adversely affects the conversion rights of any note, other than as required by the indenture;



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impair the absolute rights of any holder of a note to receive payment or delivery, as applicable, of the principal of, or the fundamental change repurchase price for, or any interest on, or the consideration due upon conversion of, such note on or after the respective due dates therefor, or to bring suit for the enforcement of any such payment or delivery on or after such due dates;



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change the ranking of the notes in a manner that adversely affects any holder;



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make any note payable in money, or at a place of payment, other than that stated in the indenture or the note;



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reduce the amount of notes whose holders must consent to any amendment, supplement, waiver or other modification; or



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make any direct or indirect change to any amendment, supplement, waiver or modification provision of the indenture or the notes that requires the consent of each affected noteholder.

For the avoidance of doubt, pursuant to the first four bullet points above, no amendment or supplement to the indenture or the notes, or waiver of any provision of the indenture or the notes, may change the amount or type of consideration due on any note (whether on an interest payment date, fundamental change repurchase date or the maturity date or upon conversion, or otherwise), or the date(s) or time(s) such consideration is payable or deliverable, as applicable, without the consent of each affected noteholder.

Notwithstanding anything to the contrary above, we and the trustee may amend or supplement the indenture or the notes without the consent of any noteholder to:

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cure any ambiguity or correct any omission, defect or inconsistency in the indenture or the notes;



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add guarantees with respect to our obligations under the indenture or the notes;



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secure the notes;



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add to our covenants or events of default for the benefit of noteholders or surrender any right or power conferred on us;



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provide for the assumption of our obligations under the indenture and the notes pursuant to, and in compliance with, the provisions described above under the caption "— Consolidation, Merger and Asset Sale";



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enter into supplemental indentures pursuant to, and in accordance with, the provisions described above under the caption "— Conversion Rights — Effect of Common Stock Change Event" in connection with a common stock change event;



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irrevocably elect or eliminate any settlement method or specified dollar amount; provided , however , that no such election or elimination will affect any settlement method theretofore elected (or deemed

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to be elected) with respect to any note pursuant to the provisions described above under the caption "— Conversion Rights — Settlement upon Conversion — Settlement Method";

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evidence or provide for the acceptance of the appointment of a successor trustee;



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conform the provisions of the indenture and the notes to this "Description of Notes" section, as supplemented by the related pricing term sheet;



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provide for or confirm the issuance of additional notes pursuant to the indenture;



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comply with any requirement of the SEC in connection with effecting or maintaining the qualification of the indenture or any supplemental indenture under the Trust Indenture Act of 1939, as amended and then in effect;



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provide for any transfer restrictions that apply to any notes issued under the indenture (other than the notes issued in this offering, and any notes issued in exchange therefor or in substitution thereof) that, at the time of their original issuance, constitute "restricted securities" within the meaning of Rule 144 under the Securities Act or that are originally issued in reliance upon Regulation S under the Securities Act; or



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make any other change to the indenture or the notes that does not, individually or in the aggregate with all other such changes, adversely affect the rights of noteholders, as such, in any material respect.

Exchange Act Reports

We will send to the trustee copies of all reports that we are required to file with the SEC pursuant to Section 13(a) or 15(d) of the Exchange Act within 15 calendar days after the date that we are required to so file the same (after giving effect to all applicable grace periods under the Exchange Act). However, we need not send to the trustee any material for which we have received, or are seeking in good faith and have not been denied, confidential treatment by the SEC. Any report that we file with the SEC through the EDGAR system (or any successor thereto) will be deemed to be sent to the trustee at the time such report is so filed via the EDGAR system (or such successor). Upon the request of any noteholder, the trustee will provide to the noteholder a copy of any report that we have sent the trustee pursuant to the provisions described above, other than a report that is deemed to be sent to the trustee pursuant to the preceding sentence. We will also comply with our other obligations under Section 314(a)(1) of the Trust Indenture Act.

Discharge

For purposes of the notes, the description below under this section titled "— Discharge" supersedes, in its entirety, the information in the accompanying prospectus under the captions "Description of Debt Securities — Defeasance" and "Description of Debt Securities — Satisfaction and Discharge," and the information in the accompanying prospectus under the caption "Description of Debt Securities — Defeasance" will not apply to the notes.

Subject to the terms of the indenture, our obligations with respect to the notes under the indenture will be discharged if we deliver all outstanding notes to the trustee for cancellation, or if all outstanding notes have become due and payable (including upon conversion, if the consideration due upon such conversion has been determined) and we have irrevocably deposited with the trustee, or caused to be delivered to noteholders, sufficient cash or other consideration to satisfy all such amounts that have become due and payable.

Calculations

Except as otherwise provided in the indenture, we will be responsible for making all calculations called for under the indenture or the notes, including determinations of the last reported sale price, the daily conversion value, the daily cash amount, the daily share amount, accrued interest on the notes and the conversion rate. We will make all calculations in good faith, and, absent manifest error, our calculations will

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be final and binding on all noteholders. We will provide a schedule of our calculations to the trustee, and the trustee will promptly forward a copy of each such schedule to any noteholder upon written request.

Trustee

The trustee under the indenture is Wells Fargo, National Association. The trustee assumes no responsibility for the accuracy or completeness of the information contained in this prospectus supplement or the related documents. The trustee and its affiliates have in the past provided and may from time to time in the future provide banking and other services to us in the ordinary course of business, including, without limitation, providing services as an underwriter and acting as a lender under our revolving credit facility.

Notices

We will send all notices or communications to noteholders pursuant to the indenture in writing by first class mail, certified or registered, return receipt requested, or by overnight air courier guaranteeing next day delivery, to the noteholders' respective addresses shown on the register for the notes. However, in the case of global notes, we are permitted to send notices or communications to noteholders pursuant to the depositary procedures, and notices and communications that we send in this manner will be deemed to have been properly sent to such noteholders in writing.

In addition, we are permitted to request that the trustee provide all notices to noteholders on our behalf.

No Personal Liability of Directors, Officers, Employees and Stockholders

No past, present or future director, officer, employee, incorporator or stockholder of ours, as such, will have any liability for any obligations of ours under the indenture or the notes or for any claim based on, in respect of, or by reason of, such obligations or their creation. By accepting any note, each noteholder will be deemed to waive and release all such liability, and such waiver and release are part of the consideration for the issuance of the notes.

Governing Law; Waiver of Jury Trial

The indenture and the notes, and any claim, controversy or dispute arising under or related to the indenture or the notes, will be governed by and construed in accordance with the laws of the state of New York. The indenture will provide that we and the trustee will irrevocably waive, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to the indenture, the notes or the transactions contemplated by the indenture or the notes.

Submission to Jurisdiction

Any legal suit, action or proceeding arising out of or based upon the indenture or the transactions contemplated by the indenture may be instituted in the federal courts of the United States of America located in the City of New York or the courts of the State of New York, in each case located in the City of New York (collectively, the "specified courts"), and each party will be deemed to irrevocably submit to the non-exclusive jurisdiction of those courts in any such suit, action or proceeding. Service of any process, summons, notice or document by mail (to the extent allowed under any applicable statute or rule of court) to any party's address as provided in the indenture will be effective service of process for any such suit, action or proceeding brought in any such court. Each of us, the trustee and each noteholder (by its acceptance of any note) will be deemed to irrevocably and unconditionally waive any objection to the laying of venue of any suit, action or other proceeding in the specified courts and to irrevocably and unconditionally waive and agree not to plead or claim any such suit, action or other proceeding has been brought in an inconvenient forum.

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Definitions

"Affiliate" has the meaning set forth in Rule 144 under the Securities Act as in effect on the date we first issue the notes.

"Bid solicitation agent" means the person who is required to obtain bids for the trading price in accordance with the provisions described under the caption "— Conversion Rights — When the Notes May Be Converted — Conversion upon Satisfaction of Note Trading Price Condition" and in the definition of "trading price."

"Board of directors" means our board of directors or a committee of such board duly authorized to act on behalf of such board.

"Business day" means any day other than a Saturday, a Sunday or any day on which the Federal Reserve Bank of New York is authorized or required by law or executive order to close or be closed.

"Capital stock" of any person means any and all shares of, interests in, rights to purchase, warrants or options for, participations in, or other equivalents of, in each case however designated, the equity of such person, but excluding any debt securities convertible into such equity.

"Close of business" means 5:00 p.m., New York City time.

"Conversion price" means, as of any time, an amount equal to (i) $1,000 divided by (ii) the conversion rate in effect at such time.

"Conversion rate" initially means                    shares of our common stock per $1,000 principal amount of notes, which amount is subject to adjustment as described above under the caption "— Conversion Rights." Whenever in this prospectus supplement we refer to the conversion rate as of a particular date without setting forth a particular time on such date, such reference will be deemed to be to the conversion rate immediately after the close of business on such date.

"Daily cash amount" means, with respect to any VWAP trading day, the lesser of (i) the applicable daily maximum cash amount; and (ii) the daily conversion value for such VWAP trading day.

"Daily conversion value" means, with respect to any VWAP trading day, one-20th of the product of (i) the conversion rate on such VWAP trading day; and (ii) the daily VWAP per share of our common stock on such VWAP trading day.

"Daily maximum cash amount" means, with respect to the conversion of any note, the quotient obtained by dividing (i) the specified dollar amount applicable to such conversion by (ii) 20.

"Daily share amount" means, with respect to any VWAP trading day, the quotient obtained by dividing (i) the excess, if any, of the daily conversion value for such VWAP trading day over the applicable daily maximum cash amount by (ii) the daily VWAP for such VWAP trading day. For the avoidance of doubt, the daily share amount will be zero for such VWAP trading day if such daily conversion value does not exceed such daily maximum cash amount.

"Daily VWAP" means, for any VWAP trading day, the per share volume-weighted average price of our common stock as displayed under the heading "Bloomberg VWAP" on Bloomberg page "MLAB <EQUITY> AQR" (or, if such page is not available, its equivalent successor page) in respect of the period from the scheduled open of trading until the scheduled close of trading of the primary trading session on such VWAP trading day (or, if such volume-weighted average price is unavailable, the market value of one share of our common stock on such VWAP trading day, determined, using a volume-weighted average price method, by a nationally recognized independent investment banking firm we select, which may include any of the underwriters). The daily VWAP will be determined without regard to after-hours trading or any other trading outside of the regular trading session.

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"Depositary procedures" means, with respect to any transfer, exchange or transaction involving a global note or any beneficial interest therein, the rules and procedures of the depositary applicable to such transfer, exchange or transaction (which, in the case of global notes registered in the name of or held by DTC or its nominee, will be DTC's procedures).

"DTC" means The Depository Trust Company.

"Ex-dividend date" means, with respect to an issuance, dividend or distribution on our common stock, the first date on which shares of our common stock trade on the applicable exchange or in the applicable market, regular way, without the right to receive such issuance, dividend or distribution (including pursuant to due bills or similar arrangements required by the relevant stock exchange). For the avoidance of doubt, any alternative trading convention on the applicable exchange or market in respect of our common stock under a separate ticker symbol or CUSIP number will not be considered "regular way" for this purpose.

"Exchange Act" means the U.S. Securities Exchange Act of 1934, as amended.

"Fundamental change" will be deemed to have occurred if, at any time after the notes are originally issued and prior to the maturity date, any of the following occurs:

  (i)  a "person" or "group" within the meaning of Section 13(d) of the Exchange Act, other than us, our "wholly owned subsidiaries" (as defined below), or any employee benefit plans of ours or any of our wholly owned subsidiaries, has become the direct or indirect "beneficial owner," as defined in Rule 13d-3 under the Exchange Act, of our common equity representing more than 50% of the voting power of our common equity and has filed a Schedule 13D or 13G (or any successor schedule, form or report), or any other schedule, form or report under the Exchange Act, disclosing such beneficial ownership; provided , however , that no "person" or "group" will be deemed to be the beneficial owner of any securities tendered pursuant to a tender or exchange offer made by or on behalf of such "person" or "group" until such tendered securities are accepted for purchase or exchange under such offer;

 (ii)  the consummation of: (1) any sale, lease or other transfer, in one transaction or a series of transactions, of all or substantially all of the assets of us and our subsidiaries, taken as a whole, to any person, other than solely to one or more of our wholly owned subsidiaries; or (2) any transaction or series of related transactions in connection with which (whether by means of merger, consolidation, share exchange, combination, reclassification, recapitalization, acquisition, liquidation or otherwise) all of our common stock is exchanged for, converted into, acquired for, or constitutes solely the right to receive, other securities, cash or other property; provided , however , that any merger, consolidation, share exchange or combination of us pursuant to which the persons that directly or indirectly "beneficially owned" all classes of our common equity immediately before such transaction directly or indirectly "beneficially own," immediately after such transaction, more than 50% of all classes of common equity of the surviving, continuing or acquiring company or other transferee, as applicable, or the parent thereof, in substantially the same proportions vis-à-vis each other as immediately before such transaction will be deemed not to be a fundamental change pursuant to this clause (ii);

(iii)  our stockholders approve any plan or proposal for our liquidation or dissolution; or

 (iv)  our common stock ceases to be listed on any of The New York Stock Exchange, The NASDAQ Global Market or The NASDAQ Global Select Market (or any of their respective successors);

provided , however , that a transaction or event described in clause (i) or (ii) above will not constitute a fundamental change if at least 90% of the consideration received or to be received by the holders of our common stock (excluding cash payments for fractional shares or pursuant to dissenters rights), in connection with such transaction or event, consists of shares of common stock listed on any of The New York Stock Exchange, The NASDAQ Global Market or The NASDAQ Global Select Market (or any of their respective successors), or that will be so listed when issued or exchanged in connection with such

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transaction or event, and such transaction or event constitutes a common stock change event whose reference property consists of such consideration.

For the purposes of this definition, any transaction or event described in both clause (i) and in clause (ii) above (without regard to the proviso in clause (ii)) will be deemed to occur solely pursuant to clause (ii) above (subject to such proviso).

For the avoidance of doubt, a merger or consolidation that is effected solely to change our jurisdiction and that satisfies either the proviso to clause (ii) above or the proviso immediately following clause (iv) above will not constitute a fundamental change.

"Holder" and "noteholder" mean a person in whose name a note is registered in the register for the notes.

"Last reported sale price" of our common stock for any trading day means the closing sale price per share (or, if no closing sale price is reported, the average of the last bid price and the last ask price per share or, if more than one in either case, the average of the average last bid prices and the average last ask prices per share) of our common stock on such trading day as reported in composite transactions for the principal U.S. national or regional securities exchange on which our common stock is then listed. If our common stock is not listed on a U.S. national or regional securities exchange on such trading day, then the last reported sale price will be the last quoted bid price per share of our common stock on such trading day in the over-the-counter market as reported by OTC Markets Group Inc. or a similar organization. If our common stock is not so quoted on such trading day, then the last reported sale price will be the average of the mid-point of the last bid price and the last ask price per share of our common stock on such trading day from a nationally recognized independent investment banking firm we select, which may include any of the underwriters.

"Make-whole fundamental change" means a fundamental change (determined after giving effect to the proviso immediately after clause (iv) of the definition thereof, but without regard to the proviso to clause (ii)(2) of such definition).

"Make-whole fundamental change conversion period" means, with respect to a make-whole fundamental change, the period from, and including, the effective date of such make-whole fundamental change to, and including, the 35th trading day after such effective date (or, if such make-whole fundamental change also constitutes a fundamental change, to, but excluding, the related fundamental change repurchase date).

"Market disruption event" means, with respect to any date, the occurrence or existence, during the one-half hour period ending at the scheduled close of trading on such date on the principal U.S. national or regional securities exchange or other market on which our common stock is listed for trading or trades, of any material suspension or limitation imposed on trading (by reason of movements in price exceeding limits permitted by the relevant exchange or otherwise) in our common stock or in any options contracts or futures contracts relating to our common stock.

"Maturity date" means August 15, 2025.

"Observation period" means, with respect to any note to be converted, (i) if the conversion date for such note occurs on or before 25th scheduled trading day immediately before the maturity date, the 20 consecutive VWAP trading days beginning on, and including, the third VWAP trading day immediately after such conversion date; and (ii) if such conversion date occurs after the 25th scheduled trading day immediately before the maturity date, the 20 consecutive VWAP trading days beginning on, and including, the 21st scheduled trading day immediately before the maturity date.

"Open of business" means 9:00 a.m., New York City time.

"Person" means any individual, corporation, partnership, limited liability company, joint venture, association, joint-stock company, trust, unincorporated organization or government or other agency or

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political subdivision thereof. Any division or series of a limited liability company, limited partnership or trust will constitute a separate "person."

"Scheduled trading day" means any day that is scheduled to be a trading day on the principal U.S. national or regional securities exchange on which our common stock is then listed or, if our common stock is not then listed on a U.S. national or regional securities exchange, on the principal other market on which our common stock is then traded. If our common stock is not so listed or traded, then "scheduled trading day" means a business day.

"Securities Act" means the U.S. Securities Act of 1933, as amended.

"Significant subsidiary" of any person means any subsidiary of that person that constitutes, or any group of subsidiaries of that person that, in the aggregate, would constitute, a "significant subsidiary" (as defined in Rule 1-02(w) of Regulation S-X under the Exchange Act) of that person.

"Specified dollar amount" means, with respect to the conversion of a note to which combination settlement applies, the maximum cash amount per $1,000 principal amount of such note deliverable upon such conversion (excluding cash in lieu of any fractional share of common stock).

"Stock price" has the following meaning for any make-whole fundamental change: (i) if the holders of our common stock receive only cash in consideration for their shares of common stock in such make-whole fundamental change and such make-whole fundamental change is pursuant to clause (ii) of the definition of "fundamental change," then the stock price is the amount of cash paid per share of our common stock in such make-whole fundamental change; and (ii) in all other cases, the stock price is the average of the last reported sale prices per share of common stock for the five consecutive trading days ending on, and including, the trading day immediately before the effective date of such make-whole fundamental change.

"Subsidiary" means, with respect to any person, (i) any corporation, association or other business entity (other than a partnership or limited liability company) of which more than 50% of the total voting power of the capital stock entitled (without regard to the occurrence of any contingency, but after giving effect to any voting agreement or stockholders' agreement that effectively transfers voting power) to vote in the election of directors, managers or trustees, as applicable, of such corporation, association or other business entity is owned or controlled, directly or indirectly, by such person or one or more of the other subsidiaries of such person; and (ii) any partnership or limited liability company where (x) more than 50% of the capital accounts, distribution rights, equity and voting interests, or of the general and limited partnership interests, as applicable, of such partnership or limited liability company are owned or controlled, directly or indirectly, by such person or one or more of the other subsidiaries of such person, whether in the form of membership, general, special or limited partnership or limited liability company interests or otherwise; and (y) such person or any one or more of the other subsidiaries of such person is a controlling general partner of, or otherwise controls, such partnership or limited liability company.

"Trading day" means any day on which (i) trading in our common stock generally occurs on the principal U.S. national or regional securities exchange on which our common stock is then listed or, if our common stock is not then listed on a U.S. national or regional securities exchange, on the principal other market on which our common stock is then traded; and (ii) there is no "market disruption event" (as defined above in this "— Definitions" section). If our common stock is not so listed or traded, then "trading day" means a business day.

"Trading price" of the notes on any trading day means the average of the secondary market bid quotations, expressed as a cash amount per $1,000 principal amount of notes, obtained by the bid solicitation agent for $1,000,000 (or such lesser amount as may then be outstanding) in principal amount of notes at approximately 3:30 p.m., New York City time, on such trading day from three nationally recognized independent securities dealers we select, which may include any of the underwriters; provided , however , that, if three such bids cannot reasonably be obtained by the bid solicitation agent but two such bids are

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obtained, then the average of the two bids will be used, and if only one such bid can reasonably be obtained by the bid solicitation agent, then that one bid will be used. If, on any trading day, (i) the bid solicitation agent cannot reasonably obtain at least one bid for $1,000,000 (or such lesser amount as may then be outstanding) in principal amount of notes from a nationally recognized independent securities dealer; (ii) we are not acting as the bid solicitation agent and we fail to instruct the bid solicitation agent to obtain bids when required; or (iii) the bid solicitation agent fails to solicit bids when required, then, in each case, the trading price per $1,000 principal amount of notes on such trading day will be deemed to be less than 98% of the product of the last reported sale price per share of our common stock on such trading day and the conversion rate on such trading day.

"VWAP market disruption event" means, with respect to any date, (i) the failure by the principal U.S. national or regional securities exchange on which our common stock is then listed, or, if our common stock is not then listed on a U.S. national or regional securities exchange, the principal other market on which our common stock is then traded, to open for trading during its regular trading session on such date; or (ii) the occurrence or existence, for more than one half hour period in the aggregate, of any suspension or limitation imposed on trading (by reason of movements in price exceeding limits permitted by the relevant exchange or otherwise) in our common stock or in any options contracts or futures contracts relating to our common stock, and such suspension or limitation occurs or exists at any time before 1:00 p.m., New York City time, on such date.

"VWAP trading day" means a day on which (i) there is no VWAP market disruption event; and (ii) trading in our common stock generally occurs on the principal U.S. national or regional securities exchange on which our common stock is then listed or, if our common stock is not then listed on a U.S. national or regional securities exchange, on the principal other market on which our common stock is then traded. If our common stock is not so listed or traded, then "VWAP trading day" means a business day.

"Wholly owned subsidiary" of a person means any subsidiary of such person all of the outstanding capital stock or other ownership interests of which (other than directors' qualifying shares) are owned by such person or one or more wholly owned subsidiaries of such person.

Book Entry, Settlement and Clearance

For purposes of the notes, the description below under this section titled "— Book Entry, Settlement and Clearance" supersedes, in its entirety, the information in the accompanying prospectus under the caption "Description of Debt Securities — Global Securities."

Global Notes

The notes will be initially issued in the form of one or more notes registered in the name of Cede & Co., as nominee of DTC, without interest coupons (the "global notes"), and will be deposited with the trustee as custodian for DTC.

Only persons who have accounts with DTC ("DTC participants") or persons who hold interests through DTC participants may own beneficial interests in a global note. We expect that, under procedures established by DTC:

§

upon deposit of a global note with DTC's custodian, DTC will credit portions of the principal amount of the global note to the accounts of the DTC participants designated by the underwriters; and



§

ownership of beneficial interests in a global note will be shown on, and transfers of such interests will be effected only through, records maintained by DTC (with respect to interests of DTC participants) and the records of DTC participants (with respect to other owners of beneficial interests in the global note).

Beneficial interests in global notes may not be exchanged for notes in physical, certificated form except in the limited circumstances described below.

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Book-Entry Procedures for Global Notes

All interests in a global note will be subject to the operations and procedures of DTC. Accordingly, you must allow for sufficient time in order to comply with those operations and procedures if you wish to exercise any of your rights with respect to the notes. The operations and procedures of DTC are controlled by DTC and may be changed at any time. None of us, the trustee or any of the underwriters will be responsible for those operations or procedures.

DTC has advised us that it is:

§

a limited purpose trust company organized under the laws of the State of New York;



§

a "banking organization" within the meaning of the New York State Banking Law;



§

a member of the Federal Reserve System;



§

a "clearing corporation" within the meaning of the Uniform Commercial Code; and



§

a "clearing agency" registered under Section 17A of the Exchange Act.

DTC was created to hold securities for its participants and to facilitate the clearance and settlement of securities transactions between its participants through electronic book-entry changes to the accounts of its participants. DTC's participants include securities brokers and dealers (including the underwriters), banks and trust companies, clearing corporations and other organizations. Indirect access to DTC's book-entry system is also available to other "indirect participants," such as banks, brokers, dealers and trust companies, who directly or indirectly clear through or maintain a custodial relationship with a DTC participant. Purchasers of notes who are not DTC participants may beneficially own securities held by or on behalf of DTC only through DTC participants or indirect participants in DTC.

So long as DTC or its nominee is the registered owner of a global note, DTC or that nominee will be considered the sole owner or holder of the notes represented by that global note for all purposes under the indenture. Except as provided below, owners of beneficial interests in a global note:

§

will not be entitled to have notes represented by the global note registered in their names;



§

will not receive or be entitled to receive physical, certificated notes; and



§

will not be considered the owners or holders of the notes under the indenture for any purpose, including, without limitation, with respect to the giving of any direction, instruction or approval to the trustee under the indenture.

As a result, each investor who owns a beneficial interest in a global note must rely on the procedures of DTC (and, if the investor is not a participant or an indirect participant in DTC, on the procedures of the DTC participant through whom the investor owns its interest) to exercise any rights of a noteholder under the indenture.

Payments on any global notes will be made by the trustee to DTC's nominee as the registered holder of the global note. Neither we nor the trustee will have any responsibility or liability for the payment of amounts to owners of beneficial interests in a global note, for any aspect of the records relating to, or payments made on account of, those interests by DTC or for maintaining, supervising or reviewing any records of DTC relating to those interests. Payments by participants and indirect participants in DTC to the owners of beneficial interests in a global note will be governed by standing instructions and customary industry practice and will be the responsibility of those participants or indirect participants and DTC.

Transfers between participants in DTC will be effected under DTC's procedures and will be settled in same-day funds.

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Certificated Notes

A global note will be exchanged, pursuant to customary procedures, for one or more physical notes only if:

§

DTC notifies us or the trustee that it is unwilling or unable to continue as depositary for such global note or DTC ceases to be a "clearing agency" registered under Section 17A of the Exchange Act and, in each case, we fail to appoint a successor depositary within 90 days of such notice or cessation;



§

an event of default has occurred and is continuing and we, the trustee or the registrar has received a written request from DTC, or from a holder of a beneficial interest in such global note, to exchange such global note or beneficial interest, as applicable, for one or more physical notes; or



§

we, in our sole discretion, permit the exchange of any beneficial interest in such global note for one or more physical notes at the request of the owner of such beneficial interest.

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