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                                                                    Exhibit 4.15

                                [FORM OF WARRANT]

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933 OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE
SOLD OR OTHERWISE DISPOSED OF EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION
STATEMENT UNDER SUCH ACT AND APPLICABLE STATE SECURITIES LAWS OR AN APPLICABLE
EXEMPTION TO THE REGISTRATION REQUIREMENTS OF SUCH ACT OR SUCH LAWS.

                               ACTERNA CORPORATION

                          Common Stock Purchase Warrant
                           Expiring December 31, 2007

                                                        New York, N.Y.
                                                        [DATE]

No. W-

                  Acterna Corporation, a Delaware corporation (the "Company"),
for value received, hereby certifies that CD&R VI (Barbados), Ltd. (the
"Purchaser"), or its permitted assigns, is entitled to purchase from the Company
[insert the number of shares of Common Stock (or other property) into which the
Purchaser's redeemed or repurchased Notes were convertible immediately prior to
early redemption or repurchase] duly authorized, validly issued, fully paid and
nonassessable shares of Common Stock, par value $.01 per share, of the Company
(the "Common Stock") at the purchase price per share determined pursuant to
Sections 1.1 and 2 hereof, subject to Section 6.7(b) of the Investment Agreement
(as defined below), at any time or from time to time after [insert date of
repurchase or redemption prior to stated maturity of applicable Notes] (the
"Issuance Date"), but prior to 5:00 P.M., New York City time, on December 31,
2007, all subject to the terms, conditions and adjustments set forth below in
this Warrant.

                  This Warrant is the Common Stock Purchase Warrant (the
"Warrant," such term to include all Warrants issued substantially in the form
hereof or in substitution therefor), originally issued on the Issuance Date in
connection with the redemption or repurchase prior to stated maturity by Acterna
LLC, a Delaware limited liability company and a wholly owned subsidiary of the
Company ("Acterna LLC") of one or more of its Senior Secured Convertible Notes
due 2007, Series 2 (the "Notes"), which were originally issued pursuant to the
Investment Agreement (the "Investment Agreement"), dated as of August 5, 2002,
among the Company, Acterna LLC and CD&R VI (Barbados), Ltd. This Warrant
evidences rights to purchase [insert number of shares of

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Common Stock set forth above] duly authorized, validly issued, fully paid and
nonassessable shares of Common Stock (such number of shares of Common Stock
referred to herein as the "Initial Exercise Shares"), subject to adjustment as
provided herein. Certain capitalized terms used in the Warrant are defined in
Section 12.

                  1. Exercise of Warrant.

                  1.1. Manner of Exercise

                  (a) Subject to Section 6.7(b) of the Investment Agreement, the
Warrant may be exercised by the holder of the Warrant or any portion hereof (the
"Holder"), in whole or in part, during normal business hours on any Business Day
on or after the Issuance Date by surrender of the Warrant, with the form of
subscription at the end hereof (or a reasonable facsimile thereof) (the
"Subscription Notice") duly executed by such Holder, to the Company at its
principal office (or, if such exercise shall be in connection with an
underwritten Public Offering of shares of Common Stock (or Other Securities)
subject to the Warrant, at the location at which the Company shall have agreed
to deliver the shares of Common Stock (or Other Securities) subject to such
offering), accompanied by payment, in cash or by wire transfer in same-day
funds, in the amount (such amount referred to herein as the "Exercise Price")
obtained by multiplying (i) the number of shares of Common Stock (without giving
effect to any adjustment provided for in Section 2) designated in such
Subscription Notice by (ii) [insert dollar amount equal to $1,000 divided by the
number of shares issuable upon conversion of $1,000 principal amount of the
Notes determined by the Conversion Rate then in effect under the Investment
Agreement], and such Holder shall thereupon be entitled to receive the number of
duly authorized, validly issued, fully paid and nonassessable shares of Common
Stock (or Other Securities) determined as provided in Section 2 hereof.

                  (b) In lieu of tendering the Exercise Price to the Company,
the holder may elect to perform a "Cashless Exercise" of the Warrant, in whole
or in part, by surrendering the Warrant to the Company, with a duly executed
Subscription Notice marked "Cashless Exercise" and designating the number of
shares of Common Stock desired by the Holder out of the total for which the
Warrant is exercisable (without giving effect to any adjustments provided for in
Section 2). The Holder shall thereupon be entitled to receive the number of duly
authorized, validly issued, fully paid and nonassessable shares of Common Stock
(or Other Securities) having a value (at the Market Price) that is equal to the
excess of (i) the then Market Price per share of Common Stock (or Other
Securities) multiplied by the number of the shares of Common Stock (or Other
Securities) (determined as of the date immediately preceding the date of any
such Subscription Notice) into which the Warrant, or portion thereof designated
by the Holder, would have been exercisable pursuant to Section 1.1(a) upon
payment of the Exercise Price by the Holder over (ii) the Exercise Price the
Holder would have been required to pay under Section 1.1(a) in respect of such
an exercise.

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                  1.2. When Exercise Deemed Effected. Each exercise of the
Warrant shall be deemed to have been effected immediately prior to the close of
business on the Business Day on which the Warrant shall have been surrendered to
the Company as provided in Section 1.1, and at such time the person or persons
in whose name or names any certificate or certificates for shares of Common
Stock (or Other Securities) shall be issuable upon such exercise as provided in
Section 1.2 shall be deemed to have become the holder or holders of record
thereof.

                  1.3. Delivery of Stock Certificates, etc. As soon as
practicable after the exercise of the Warrant, in whole or in part, and in any
event within five Business Days thereafter (unless such exercise shall be in
connection with an underwritten Public Offering of shares of Common Stock (or
Other Securities) subject to the Warrant, in which event, concurrently with such
exercise), the Company at its expense (including the payment by it of any taxes
applicable to an issuer upon the issuance of shares, but excluding transfer
taxes) shall cause to be issued in the name of and delivered to the Holder or,
subject to Section 6, as such Holder (upon payment by such Holder of any
applicable transfer taxes) may direct,

                  (a) a certificate or certificates for the number of duly
authorized, validly issued, fully paid and nonassessable shares of Common Stock
(or Other Securities) to which such Holder shall be entitled upon such exercise
plus, in lieu of any fractional share to which such Holder would otherwise be
entitled, cash in an amount equal to the same fraction of the Market Price per
share of such Common Stock (or Other Securities) on the Business Day next
preceding the date of such exercise, and

                  (b) in case such exercise is in part only, a new Warrant or
Warrants of like tenor, calling in the aggregate on the face or faces thereof
for the number of shares of Common Stock equal (without giving effect to any
adjustment therein) to the number of such shares called for on the face of the
Warrant minus the number of such shares designated by the Holder upon such
exercise as provided in Section 1.1.

                  1.4. Company to Reaffirm Obligations. The Company shall, at
the time of or at any time after each exercise of the Warrant, upon the request
of the Holder, acknowledge in writing its continuing obligation to afford to
such Holder all rights (including, without limitation, any right of registration
of any shares of Common Stock (or Other Securities) issuable upon exercise of
the Warrant pursuant to Section 7) to which such Holder shall continue to be
entitled after such exercise in accordance with the terms of the Warrant,
provided that if any such Holder shall fail to make any such request, the
failure shall not affect the continuing obligation of the Company to afford such
rights to such Holder.

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                  2. Adjustment of Common Stock Issuable upon Exercise.

                  2.1. Number of Shares; Warrant Price. The number of shares of
Common Stock which the Holder shall be entitled to receive upon each exercise
hereof shall be determined by multiplying the number of shares of Common Stock
which would otherwise (but for any application of the provisions of this Section
2) be issuable upon such exercise, as designated by the Holder pursuant to
Section 1.1, by a fraction of which (i) the numerator is $[insert dollar amount
equal to $1,000 divided by the number of shares issuable upon conversion of
$1,000 principal amount of the Notes determined by the Conversion Rate then in
effect with respect to any particular Note under the Investment Agreement] and
(ii) the denominator is the Warrant Price (as defined below) in effect on the
date of such exercise. The "Warrant Price," which shall initially be $[insert
dollar amount equal to $1,000 divided by the number of shares issuable upon
conversion of $1,000 principal amount of the Notes determined by the Conversion
Rate then in effect with respect to any particular Note under the Investment
Agreement] and shall be adjusted and readjusted from time to time as provided in
Section 2 hereof and, as so adjusted or readjusted, shall remain in effect until
a further adjustment or readjustment thereof is required by Section 2.

                  2.2. Stock Dividends, Subdivisions and Combinations. If at any
time the Company shall:

                  (i)   issue or deliver any shares of Common Stock as a result
         of the declaration or payment of a dividend of Common Stock payable in,
         or other distribution to holders of Common Stock of, shares of Common
         Stock,

                  (ii)  subdivide its outstanding shares of Common Stock into a
         larger number of shares of Common Stock, or

                  (iii) combine its outstanding shares of Common Stock into a
         smaller number of shares of Common Stock,

then the Warrant Price then in effect shall be adjusted to equal (1) the Warrant
Price in effect immediately prior to such event multiplied by the number of
shares of Common Stock for which the Warrant is exercisable immediately prior to
the adjustment divided by (2) the number of shares of Common Stock which a
record holder of the same number of shares of Common Stock for which the Warrant
is exercisable immediately prior to the happening of such event would own or be
entitled to receive after the happening of such event.

                  2.3. Extraordinary Dividends and Distributions. If at any time
the Company shall distribute to all holders of its outstanding Common Stock
evidences of indebtedness of the Company, cash or assets or securities other
than the Common Stock

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(any such evidences of indebtedness, cash, assets or securities, the "Assets"),
then, in each case, the Warrant Price then in effect shall be reduced to a price
determined by multiplying such Warrant Price by a fraction,

                  (i)  the numerator of which shall be the Market Price then in
         effect less the value of such Assets applicable to one share of Common
         Stock, and

                  (ii) the denominator of which shall be such Market Price.

                  Any adjustment required by this Section 2.3 shall be made
whenever any such distribution is made, and shall become effective on the date
of distribution retroactive to the record date for the determination of
shareholders entitled to receive such distribution.

                  2.4. Issuance of Additional Shares of Common Stock.

                  (a) If at any time after the date hereof the Company shall
(except as hereinafter provided) issue or sell any Additional Shares of Common
Stock (other than pursuant to Section 2.5 or Section 2.6) without consideration
or in exchange for consideration in an amount per Additional Share of Common
Stock (such consideration for purposes of this Section 2.4, the "New Issue
Price") less than the Market Price of such securities, then the Warrant Price
then in effect shall be reduced to a price determined by multiplying such
Warrant Price by a fraction,

                  (i) the numerator of which shall be (x) the number of shares
         of Common Stock outstanding immediately prior to such issue or sale
         plus (y) the number of shares of Common Stock which the aggregate
         consideration received by the Company for the total number of such
         Additional Shares of Common Stock so issued or sold would purchase at
         such Market Price, and

                  (ii) the denominator of which shall be the number of shares of
         Common Stock outstanding immediately after such issue or sale.

                  (b) The provisions of paragraph (a) of this Section 2.4 shall
   not apply to any issuance of Additional Shares of Common Stock for which an
adjustment is provided under Section 2.2.

                  2.5. Issuance of Warrants or Other Rights. If at any time
after the date hereof the Company shall take a record of holders of Common Stock
for the purpose of entitling them to receive a distribution of, or shall in any
manner (whether directly or by assumption in a merger in which the Company is
the surviving corporation) issue or sell, any warrants or other rights to
subscribe for or purchase any Additional Shares of Common Stock or any
Convertible Securities, whether or not such rights thereunder are immediately
exercisable, and the price per share (such price per share for purposes of this

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Section 2.5, the "New Issue Price") for which Common Stock is issuable upon the
exercise of such warrants or other rights or upon conversion or exchange of such
Convertible Securities shall be less than the Market Price, then the Warrant
Price shall be adjusted as provided in Section 2.4 on the basis that the maximum
number of shares of Common Stock issuable pursuant to all such warrants or other
rights or necessary to effect the conversion or exchange of all such Convertible
Securities shall be deemed to have been issued and outstanding and the Company
shall have received all of the consideration payable therefor, if any, as of the
date of the actual issuance of such warrants or other rights. No further
adjustments of the Warrant Price shall be made upon the actual issuance of such
Common Stock or of such Convertible Securities upon exercise of such warrants or
other rights or upon the actual issuance of such Common Stock upon such
conversion or exchange of such Convertible Securities.

                  2.6. Issuance of Convertible Securities. If at any time the
Company shall take a record of the holders of Common Stock for the purpose of
entitling them to receive a distribution of, or shall in any manner (whether
directly or by assumption in a merger in which the Company is the surviving
corporation) issue or sell, any Convertible Securities, whether or not the
rights to exchange or convert thereunder are immediately exercisable, and the
price per share (such price per share for purposes of this Section 2.6, the "New
Issue Price") for which Common Stock is issuable upon such conversion or
exchange shall be less than the Market Price, then the Warrant Price shall be
adjusted as provided in Section 2.4 on the basis that the maximum number of
shares of Common Stock necessary to effect the conversion or exchange of all
such Convertible Securities shall be deemed to have been issued and outstanding
and the Company shall have received all of the consideration payable therefor,
if any, as of the date of actual issuance of such Convertible Securities. No
adjustment of the Warrant Price shall be made under this Section 2.6 upon the
issuance of any Convertible Securities which are issued pursuant to the exercise
of any warrants or other subscription or purchase rights therefor, if any such
adjustment shall previously have been made upon the issuance of such warrants or
other rights pursuant to Section 2.5. No further adjustments of the Warrant
Price shall be made upon the actual issuance of such Common Stock upon
conversion or exchange of such Convertible Securities, and, if any issuance or
sale of such Convertible Securities is made upon exercise of any warrant or
other right to subscribe for or to purchase any such Convertible Securities for
which adjustments of the Warrant Price have been or are to be made pursuant to
other provisions of this Section 2, no further adjustments of the Warrant Price
shall be made by reason of such issuance or sale.

                  The provisions of Sections 2.4, 2.5 and 2.6 shall not apply to
any issuance of Notes or Warrants, or Common Stock in exchange therefor or upon
exercise thereof, pursuant to the Investment Agreement.

                  2.7. Superseding Adjustment. If, at any time after any
adjustment of the number of shares of Common Stock for which the Warrant is
exercisable shall have been

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made pursuant to Section 2.5 or 2.6 as the result of any issuance of warrants,
rights or Convertible Securities,

                  (i)  such warrants or rights, or the right of conversion or
         exchange in such other Convertible Securities, shall expire, and all or
         a portion of such warrants or rights, or the right of conversion or
         exchange with respect to all or a portion of such other Convertible
         Securities, as the case may be, shall not have been exercised, or

                  (ii) the consideration per share for which shares of Common
         Stock are issuable pursuant to such warrants or rights, or the terms of
         such other Convertible Securities, shall be increased solely by virtue
         of provisions therein contained for an automatic increase in such
         consideration per share upon the occurrence of a specified date or
         event,

then such previous adjustment shall be rescinded and annulled and the shares of
Common Stock which were deemed to have been issued by virtue of the computation
made in connection with the adjustment so rescinded and annulled shall no longer
be deemed to have been issued by virtue of such computation. Thereupon, a
recomputation shall be made of the effect of such rights or options or other
Convertible Securities effective as of the date of such previous adjustment on
the basis of

                  (A) treating the number of shares of Common Stock or other
         property, if any, theretofore actually issued or issuable pursuant to
         the previous exercise of any such warrants or rights or any such right
         of conversion or exchange, as having been issued on the date or dates
         of any such exercise and for the consideration actually received and
         receivable therefor, and

                  (B) treating any such warrants or rights or any such other
         Convertible Securities which then remain outstanding as having been
         granted or issued immediately after the time of such increase of the
         consideration per share for which shares of Common Stock or other
         property are issuable under such warrants or rights or other
         Convertible Securities,

whereupon a new adjustment of the number of shares of Common Stock for which the
Warrant is exercisable shall be made effective as of the date of such previous
adjustment, which new adjustment shall supersede the previous adjustment so
rescinded and annulled. Any reduction in the number of shares of Common Stock
for which the Warrant is exercisable as a result of this Section 2.7 shall be
applied in its entirety to the number of shares of Common Stock for which the
Warrant is exercisable as of the date such new adjustment is made.

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                  2.8. Consolidation, Merger, Sale of Assets, Reorganization,
etc. (a) In case at any time the Company shall be a party to any transaction
(including without limitation a merger, consolidation, sale of all or
substantially all of the Company's assets or recapitalization of the Common
Stock) in which the previously outstanding Common Stock shall be changed into or
exchanged for different securities of the Company or changed into or exchanged
for common stock or other securities of another corporation or interests in a
noncorporate entity or other property (including cash) or any combination of any
of the foregoing (each such transaction being hereinafter referred to as the
"Transaction") then, as a condition to the consummation of the Transaction,
lawful and adequate provisions shall be made so that, upon the basis and terms
and in the manner provided in this Section 2.8, the Holder, upon the exercise of
the Warrant, shall be entitled to receive, in lieu of the Common Stock issuable
upon such exercise prior to such consummation, the stock and other securities,
cash and property to which the Holder would have been entitled upon the
consummation of the Transaction if the Holder had exercised the Warrant
immediately prior thereto, subject to adjustments (subsequent to such
consummation) as nearly equivalent as possible to the adjustments provided for
in Section 2.

                  (b) Notwithstanding anything contained herein to the contrary,
the Company will not effect any Transaction unless, prior to the consummation
thereof, each corporation or entity (other than the Company) which may be
required to deliver any stock, securities, cash or property upon the exercise of
the Warrant as provided herein shall assume, by written instrument delivered to
the Holder, (i) the obligations of the Company hereunder (and if the Company
shall survive the consummation of such Transaction, such assumption shall be in
addition to, and shall not release the Company from, any continuing obligations
of the Company hereunder) and (ii) the obligation to deliver to the Holder such
shares of stock, securities, cash or property as, in accordance with the
foregoing provisions, the Holder may be entitled to receive, and the terms
hereof (including, without limitation, all of the applicable provisions of
Section 2) shall be applicable to the stock, securities, cash or property which
such corporation or entity may be required to deliver upon any conversion of any
Warrants or the exercise of any rights pursuant hereto.

                  (c) Upon any liquidation, dissolution or winding up of the
Company, the Holder shall receive such cash or property (less the Warrant Price)
which the Holder would have been entitled to receive upon the happening of such
liquidation, dissolution or winding up had the Warrant been exercised in full
and the shares of Common Stock in respect of such exercise issued immediately
prior to the occurrence of such liquidation, dissolution or winding-up.

                  2.9. Other Dilutive Events. In case any event shall occur as
to which the provisions of Section 2 are not strictly applicable but as to which
the failure to make any adjustment would not fairly protect the exercise rights
with respect to the Warrant in

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accordance with the essential intent and principles of such Section, then, in
each such case, the Company shall appoint a firm of independent certified public
accountants of recognized national standing (which may be the regular auditors
of the Company), which shall give their opinion upon the adjustment, if any, on
a basis consistent with the essential intent and principles established in
Section 2, necessary to preserve, without dilution, the exercise rights
represented by the Warrant. Upon receipt of such opinion, the Company will
promptly mail a copy thereof to the Holder of the Warrant and shall make the
adjustments, if any, described therein.

                  2.10. No Dilution or Impairment. The Company will not, by
amendment of its certificate of incorporation or through any consolidation,
merger, reorganization, transfer of assets, dissolution, issue or sale of
securities or any other voluntary action, avoid or seek to avoid the observance
or performance of any of the terms hereof, but will at all times in good faith
assist in the carrying out of all such terms and in the taking of all such
action as may be reasonably necessary or appropriate in order to protect the
rights of the Holders of this Warrant against dilution in respect of which the
Holders are not fully protected by this Section 2 or other impairment. Without
limiting the generality of the foregoing, the Company:

                  (a) will not permit the par value $.01 per share, if any, of
any shares of Common Stock receivable upon the exercise of the Warrant to exceed
the amount payable therefor upon such exercise,

                  (b) will take all such action as may be necessary or
appropriate in order that the Company may validly and legally issue fully paid
and nonassessable shares of stock on the exercise of the Warrant from time to
time outstanding,

                  (c) will not take or permit to be taken any action which
results in any adjustment of the Warrant Price if the total number of shares of
Common Stock (or Other Securities) issuable after such action upon the complete
exercise of the Warrant would exceed the total number of shares of Common Stock
(or Other Securities) then authorized by the Company's articles of incorporation
and available for the purpose of issue upon such exercise, and

                  (d) will not (i) issue any equity securities (other than
Common Stock or Convertible Securities) that participate with the shares of
Common Stock in dividends, distributions and/or other rights ("Other Dilutive
Securities"), or (ii) declare or make dividends or distributions (whether of
evidences of indebtedness of the Company, cash, assets or securities, including,
without limitation, options, warrants or other rights to acquire Common Stock)
in respect of any Other Dilutive Securities or Convertible Securities, unless,
in each case, this Section 2 is first amended so as to provide the Holders of
the Warrant with full protection against dilution caused by or resulting from
such issuances, dividends or distributions.

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                  2.11. Other Provisions Applicable to Adjustments under this
Section 2. The following provisions shall be applicable to the making of
adjustments to the number of shares of Common Stock for which the Warrant is
exercisable provided for in this Section 2:

                  (i)   Computation of Consideration. To the extent that any
         shares of Common Stock or any Convertible Securities or any warrants or
         other rights to subscribe for or purchase any shares of Common Stock or
         any Convertible Securities shall be issued for cash consideration, the
         cash consideration received by the Company therefor shall be the amount
         of the cash received by the Company therefor, or, if such shares of
         Common Stock or Convertible Securities are offered by the Company for
         subscription, the subscription price, or, if such shares of Common
         Stock or Convertible Securities are sold to underwriters or dealers for
         public offering without a subscription offering, the initial public
         offering price (in any such case subtracting any amounts paid or
         receivable for accrued interest or accrued dividends and taking into
         account any compensation, discounts or expenses paid or incurred by the
         Company for and in the underwriting of, or otherwise in connection
         with, the issuance thereof). To the extent that such issuance shall be
         for a consideration other than cash, then, except as herein otherwise
         expressly provided, the amount of such non-cash consideration shall be
         deemed to be the fair market value of such consideration at the time of
         such issuance as determined in good faith by the Board of Directors of
         the Company. In case any shares of Common Stock or any Convertible
         Securities or any warrants or other rights to subscribe for or purchase
         such shares of Common Stock or Convertible Securities shall be issued
         in connection with any merger in which the Company issues any
         securities, the amount of consideration therefor shall be deemed to be
         the fair market value, as determined by an independent investment
         banking firm retained by the Company, which firm may be an independent
         investment banking firm regularly retained by the Company, of such
         portion of the assets and business of the nonsurviving corporation as
         such firm shall determine to be attributable to such shares of Common
         Stock, Convertible Securities, warrants or other rights, as the case
         may be. The consideration for any shares of Common Stock issuable
         pursuant to any warrants or other rights to subscribe for or purchase
         the same shall be the consideration received by the Company for issuing
         such warrants or other rights plus the additional consideration payable
         to the Company upon exercise of such warrants or other rights. The
         consideration for any shares of Common Stock issuable pursuant to the
         terms of any Convertible Securities shall be the consideration, if any,
         received by the Company for issuing warrants or other rights to
         subscribe for or purchase such Convertible Securities, plus the
         consideration paid or payable to the Company in respect of the
         subscription for or purchase of such Convertible Securities, plus the
         additional consideration, if any, payable to the Company upon the
         exercise of the right of conversion or exchange in such Convertible
         Securities.

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         In case of the issuance at any time of any shares of Common Stock or
         Convertible Securities in payment or satisfaction of any dividends upon
         any class of stock other than Common Stock, the Company shall be deemed
         to have received for such shares of Common Stock or Convertible
         Securities a consideration equal to the amount of such dividend so paid
         or satisfied.

                  (ii)  Computation of Asset Value. To the extent that any
         Assets shall be distributed to all holders of the Company's outstanding
         Common Stock in cash, the value of such Assets shall be the amount of
         cash so distributed, or, if such Assets are securities offered by the
         Company for subscription, the subscription price, or if such Assets are
         securities sold to underwriters or dealers for public offering without
         a subscription offering, the initial public offering price (in any such
         case adding any accrued interest or dividends but without taking into
         account any compensation, discounts or expenses paid or incurred by the
         Company in connection therewith). To the extent that the Company shall
         so distribute Assets other than cash, except as herein otherwise
         expressly provided, then the value of such Assets shall be deemed to be
         fair value of such Assets at the time of such distribution as
         determined in good faith by the Board of Directors of the Company.

                  (iii) When Adjustment to Be Made. The adjustments required by
         this Section 2 shall be made whenever and as often as any specified
         event requiring an adjustment shall occur, except that any adjustment
         of the number of shares of Common Stock for which the Warrant is
         exercisable that would otherwise be required may be postponed (except
         in the case of a subdivision or combination of shares of the Common
         Stock, as provided for in Section 2.2) up to but not beyond the date of
         exercise if such adjustment either by itself or with other adjustments
         not previously made adds or subtracts less than 1% of the shares of
         Common Stock for which the Warrant is exercisable immediately prior to
         the making of such adjustment. Any adjustment representing a change of
         less than such minimum amount (except as aforesaid) which is postponed
         shall be carried forward and made as soon as such adjustment, together
         with other adjustments required by this Section 2 and not previously
         made, would result in a minimum adjustment or on the date of exercise.
         For the purpose of any adjustment, any specified event shall be deemed
         to have occurred at the close of business on the date of its
         occurrence.

                  (iv)  Fractional Interest; Rounding. In computing adjustments
         under this Section 2, fractional interests in Common Stock shall be
         taken into account to the nearest 1/10th of a share, and adjustments in
         the Warrant Price shall be made to the nearest $.01.

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                  (v)   When Adjustment Not Required. If the Company shall take
         a record of the holders of its Common Stock for the purpose of
         entitling them to receive subscription or purchase rights and shall,
         thereafter and before the distribution to shareholders thereof, legally
         abandon its plan to deliver such subscription or purchase rights, then
         no adjustment shall be required by reason of the taking of such record
         and any such adjustment previously made in respect thereof shall be
         rescinded and annulled.

                  (vi)  Escrow of Warrant Stock. If the Holder exercises the
         Warrant after any property becomes distributable by reason of the
         taking of any record of the holders of Common Stock as described in
         this Section 2, but prior to the occurrence of the event for which such
         record is taken, any shares of Common Stock issuable upon exercise by
         reason of any adjustment required by this Section 2 shall be deemed the
         last shares of Common Stock for which the Warrant is exercised
         (notwithstanding any other provision to the contrary herein). Such
         shares or other property shall be held in escrow for the Holder by the
         Company to be issued to the Holder upon and to the extent that the
         event actually takes place, upon payment of the Exercise Price.
         Notwithstanding any other provision to the contrary herein, if the
         event for which such record was taken fails to occur or is rescinded,
         then such escrowed shares shall be canceled by the Company and escrowed
         property returned.

                  (vii) Shareholder Rights Plans. Rights or warrants distributed
         by the Company to all holders of Common Stock pursuant to a shareholder
         rights plan (or "poison pill") entitling the holders thereof to
         subscribe for or purchase shares of the Company's capital stock, which
         rights or warrants, until the occurrence of a specified event or events
         (a "Trigger Event"), (x) are deemed to be transferred with the Common
         Stock in respect of which they are issued, (y) are not exercisable, and
         (z) are also issued in respect of future issuances of Common Stock,
         shall be deemed not to have been distributed for purposes of Section
         2.5 and 2.6 (and no adjustment to the Warrant Price under those
         Sections shall be required) until first the occurrence of a Trigger
         Event, unless the Trigger Event is rescinded within 15 days. If upon
         the occurrence of any event such right or warrant becomes exercisable
         to purchase different securities, evidences of indebtedness or other
         assets or entitles its holder to purchase a different amount of the
         foregoing or to purchase any of the foregoing at a different purchase
         price (an "Other Trigger Event"), then the occurrence of each such
         Other Trigger Event, unless the Other Trigger Event is rescinded within
         15 days, shall be deemed to be the date of issuance and Record Date
         with respect to a new right or warrant (and a termination or expiration
         of the existing right or warrant without exercise by the holder thereof
         to the extent not actually exercised). In addition, in the event of any
         distribution (or deemed distribution) of rights or warrants, or any
         Trigger Event or Other Trigger Event with respect thereto, that
         resulted in an adjustment

                                       12

<PAGE>

         of the Warrant Price under Section 2.5 or 2.6, (1) in the case of any
         such rights or warrants which shall have been redeemed or repurchased
         without exercise by the holders thereof, the Warrant Price shall be
         adjusted upon such redemption or repurchase to give effect to such
         distribution, Trigger Event or Other Trigger Event, as the case may be,
         as though it were an extraordinary cash distribution equal to the
         per-share redemption or repurchase price received by a holder of Common
         Stock with respect to such rights or warrants (assuming such holder had
         retained such rights), made to all holders of Common Stock on the date
         of such redemption or repurchase, and (2) in the case of such rights or
         warrants all of which shall have expired or been terminated without
         exercise, the Warrant Price shall be readjusted as if such rights or
         warrants had never been issued.

                  2.12. Exercise Rights Subject to Stockholder Vote. If,
pursuant to any Requirement of Law or rule or regulation of any securities
exchange or national securities quotation service, the stockholders of the
Parent are required to approve the issuance of shares of Common Stock issuable
upon exercise of this Warrant, this Warrant may not be exercised until such
issuance upon exercise has been so approved at the next annual meeting of the
Parent's stockholders or otherwise. At any time prior to such approval, upon the
written request of the Purchaser, the Parent, at its own expense and as soon as
practicable following such request, shall seek the written consent or approval
of its stockholders to such issuance upon exercise of this Warrant, prepare and
file with the SEC an information statement relating to such stockholder approval
and take all other actions as are necessary or advisable under any Requirement
of Law or otherwise in respect of the issuance of Common Stock upon exercise of
this Warrant.

                  3. Notice of Adjustment. Whenever the number of shares of
Common Stock for which the Warrant is exercisable or the Warrant Price shall be
adjusted pursuant to Section 2, the Company shall forthwith prepare a
certificate to be executed by the chief financial officer of the Company setting
forth, in reasonable detail, the event requiring the adjustment, the method by
which the adjustment was calculated, the number of shares of Common Stock for
which the Warrant is exercisable and the Warrant Price after giving effect to
such adjustment or change. The Company shall promptly cause a signed copy of
such certificate to be delivered to the Holder. The Company shall keep at the
office of the Company copies of all such certificates and cause the same to be
available for inspection during normal business hours by the Holder.

                  4. Accountants' Report as to Adjustments. In each case of any
adjustment or readjustment to the shares of Common Stock (or Other Securities)
issuable upon the exercise of the Warrant, the Company at its expense shall
promptly compute such adjustment or readjustment in accordance with the terms of
the Warrant and cause independent public accountants of recognized national
standing selected by the Company (which may be the regular auditors of the
Company) to verify such computation and prepare a report setting forth such
adjustment or readjustment and showing in reasonable

                                       13

<PAGE>

detail the method of calculation thereof and the facts upon which such
adjustment or readjustment is based, including without limitation a statement of
(a) the consideration received or to be received by the Company for any shares
of Common Stock issued or sold or deemed to have been issued, (b) the number of
shares of Common Stock outstanding or deemed to be outstanding, and (c) the
Warrant Price in effect immediately prior to such issuance or sale and as
adjusted and readjusted (if required by Section 2) on account thereof. The
Company shall forthwith mail a copy of each such report to each Holder and
shall, upon the written request at any time of any Holder, furnish to such
Holder a like report setting forth the Warrant Price at the time in effect and
showing in reasonable detail how it was calculated. The Company shall also keep
copies of all such reports at its principal office and shall cause the same to
be available for inspection at such office during normal business hours by any
Holder or any prospective purchaser of a Warrant designated by the Holder.

                  5. Notices of Corporate Action. In the event of

                  (a) any taking by the Company of a record of the holders of
its Common Stock for the purpose of determining the holders thereof who are
entitled to receive any dividend payable in, or other distribution of, shares of
Common Stock, or any other dividend or other distribution, or any right to
subscribe for, purchase or otherwise acquire any shares of Common Stock or any
Convertible Securities, or to receive any other right,

                  (b) any subdivision of outstanding shares of Common Stock into
a larger number of shares of Common Stock, or any combination of such shares
into smaller number of shares of Common Stock,

                  (c) any capital reorganization of the Company, any
reclassification or recapitalization of the capital stock of the Company or any
consolidation or merger involving the Company and any other Person or any
transfer of all or substantially all the assets of the Company to any other
Person, or

                  (d) any voluntary or involuntary dissolution, liquidation or
winding-up of the Company,

the Company shall mail to each Holder a notice specifying (i) the date or
expected date on which any such record is to be taken for the purpose of such
dividend, distribution or right, and the amount and character of such dividend,
distribution or right, (ii) the date or expected date on which any such
subdivision, combination or issuance is to take place, and the amount of Common
Stock that shall be the subject of such subdivision, combination or issuance and
(iii) the date or expected date on which any such reorganization,
reclassification, recapitalization, consolidation, merger, transfer,
dissolution, liquidation or winding-up is to take place and the time, if any
such time is to be fixed, as of which the holders of record of Common Stock (or
Other Securities) shall

                                       14

<PAGE>

be entitled to exchange their shares of Common Stock (or Other Securities) for
the securities or other property deliverable upon such reorganization,
reclassification, recapitalization, consolidation, merger, transfer,
dissolution, liquidation or winding-up. Such notice shall be mailed no later
than 15 Business Days prior to the date specified in subdivisions (i), (ii) and
(iii) above.

                  6. Legend, etc. Except as otherwise permitted by this Section
6, the Warrant originally issued pursuant to the Investment Agreement, each
Warrant issued upon direct or indirect transfer or in substitution for any
Warrant pursuant to Section 12 hereof, each certificate for Common Stock (or
Other Securities) issued upon the exercise of any Warrant and each certificate
issued upon the direct or indirect transfer of any such Common Stock (or Other
Securities) (other than shares of Common Stock (or Other Securities) or Warrants
which have been transferred in a transaction registered under the Securities Act
or exempt from the registration requirements of the Securities Act pursuant to
Rule 144 thereunder or any similar rule or regulation) shall bear the following
legend (or a reasonable facsimile):

         "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
         REGISTERED UNDER THE SECURITIES ACT OF 1933 OR THE SECURITIES
         LAWS OF ANY STATE AND MAY NOT BE SOLD OR OTHERWISE DISPOSED OF EXCEPT
         PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH ACT AND
         APPLICABLE STATE SECURITIES LAWS OR AN APPLICABLE EXEMPTION TO THE
         REGISTRATION REQUIREMENTS OF SUCH ACT OR SUCH LAWS."

                  The restrictions imposed by this Section 6 shall cease and
terminate as to any particular securities (a) when such securities shall have
been effectively registered under the Securities Act and disposed of in
accordance with the registration statement covering such securities, (b) when,
in the opinion of counsel for the Holder (which counsel shall be reasonably
acceptable to the Company), such restrictions are no longer required in order to
insure compliance with the Securities Act, or (c) when such securities have been
beneficially owned, by a Person who has not been an Affiliate of the Company for
at least three months, for a period of at least two years (or such shorter
period as may be applicable under Rule 144(k) under the Securities Act or any
successor thereto), all as determined under Rule 144 under the Securities Act.
Whenever such restrictions shall terminate as to any securities, as soon as
practicable thereafter and in any event within five days, the Holder thereof
shall be entitled to receive from the Company, without expense (other than
transfer taxes, if any), new securities of like tenor not bearing the applicable
legend set forth in this Section 6.

                  7. Registration Rights. All shares of Common Stock (and Other
Securities) issuable or issued upon the exercise of the Warrant are subject to
and entitled

                                       15

<PAGE>

to the benefits of the registration rights and other provisions set forth in the
Registration Rights Agreement.

                  8. Availability of Information. The Company shall comply with
the reporting requirements of sections 13 and 15(d) of the Exchange Act (whether
or not it shall be required to do so pursuant to such sections) and shall comply
with all public information reporting requirements of the Commission (including
Rule 144 promulgated by the Commission under the Securities Act) from time to
time in effect and relating to the availability of an exemption from the
Securities Act for the sale of any Restricted Securities. The Company shall
cooperate with each holder of any Restricted Securities in supplying such
information as may be necessary for such holder to complete and file any
information reporting forms presently or hereafter required by the Commission as
a condition to the availability of an exemption from the Securities Act for the
sale of any Restricted Securities. The Company shall furnish to the Holder, or
to any Holder of a portion of the Warrant, promptly upon their becoming
available, copies of all reports on Form 10-K and Form 10-Q and proxy statements
filed by the Company with the Commission, and copies of all regular and periodic
reports and all registration statements and prospectuses filed by the Company
with any securities exchange or with the Commission.

                  9. Reservation of Stock, etc. The Company shall at all times
reserve and keep available, solely for issuance and delivery upon exercise of
the Warrant, the number of shares of Common Stock (or Other Securities) from
time to time issuable upon exercise of the Warrant at the time outstanding. All
shares of Common Stock (or Other Securities) shall be duly authorized and, when
issued upon such exercise, shall be validly issued and, in the case of shares,
fully paid and nonassessable with no liability on the part of the holders
thereof.

                  10. Listing on Securities Exchanges. The Company shall list on
each national securities exchange (or the Nasdaq National Market or the Nasdaq
SmallCap Market) on which any Common Stock may at any time be listed, and shall
maintain such listing of, all shares of Common Stock from time to time issuable
upon the exercise of the Warrant, subject to official notice of issuance upon
the exercise of the Warrant. The Company shall also so list on each national
securities exchange, the Nasdaq National Market or the Nasdaq SmallCap Market,
and shall maintain such listing of, any Other Securities, if at the time any
securities of the same class shall be listed on such national securities
exchange, the Nasdaq National Market or the Nasdaq SmallCap Market, as the case
may be.

                  11. Ownership, Transfer and Substitution of the Warrant. (a)
Ownership of Warrant. The Company may treat the Person in whose name the
Warrant, or any Warrant or Warrants issued in substitution therefor, is
registered on the register kept at the principal office of the Company as the
owner and the Holder thereof for all purposes,

                                       16

<PAGE>

notwithstanding any notice to the contrary, except that, if and when any Warrant
is properly assigned in blank, the Company may (but shall not be obligated to)
treat the bearer thereof as the owner of such Warrant for all purposes,
notwithstanding any notice to the contrary. Subject to Section 6, a Warrant, if
properly assigned, may be exercised by a new Holder without first having a new
Warrant issued.

                  (b) Transfer and Exchange of the Warrant. Upon the surrender
of the Warrant, properly endorsed, for registration of transfer or for exchange
at the principal office of the Company, the Company at its expense shall
(subject to compliance with Section 6, if applicable) execute and deliver to or
upon the order of the Holder thereof a new Warrant or Warrants of like tenor, in
the name of such Holder or as such Holder (upon payment by such Holder of any
applicable transfer taxes) may direct, calling in the aggregate on the face or
faces thereof for the number of shares of Common Stock called for on the face or
faces of the Warrant or Warrants so surrendered.

                  (c) Replacement of the Warrant. Upon receipt of evidence
reasonably satisfactory to the Company of the loss, theft, destruction or
mutilation of any Warrant and, in the case of any such loss, theft or
destruction of any Warrant held by a Person other than the Purchaser, upon
delivery of indemnity reasonably satisfactory to the Company in form and amount
or, in the case of any such mutilation, upon surrender of such Warrant for
cancellation at the principal office of the Company, the Company at its expense
shall execute and deliver, in lieu thereof, a new Warrant of like tenor.

                  12. Definitions. As used herein, unless the context otherwise
requires, the following terms have the following respective meanings:

                  Additional Shares of Common Stock: all shares (including
treasury shares) of Common Stock issued or sold by the Company after the
Issuance Date, whether or not subsequently reacquired or retired by the Company,
other than shares of Common Stock issued (i) upon the exercise of this Warrant
or any other Warrant issued by the Company pursuant to the Investment Agreement
or (ii) upon conversion of the Notes.

                  Affiliate: with respect to any Person, any Person that
directly or indirectly, through one or more intermediaries, controls, or is
controlled by, or is under common control with, such Person.

                  Assets:  the meaning specified in Section 2.3.

                  Beneficially Own: with respect to any securities shall mean
having "beneficial ownership" of such securities (as determined pursuant to Rule
13d-3 under the Exchange Act), including pursuant to any agreement, arrangement
or understanding, whether or not in writing.

                                       17

<PAGE>

                  Business Day: any day other than a Saturday or a Sunday or a
day on which commercial banking institutions in the City of New York are
authorized by law to be closed, provided that, in determining the period within
which certificates or Warrants are to be issued and delivered pursuant to
Section 1.3 at a time when shares of Common Stock (or Other Securities) are
listed or admitted to trading on any national securities exchange or in the
over-the-counter market and in determining the Market Price of any securities
listed or admitted to trading on any national securities exchange or in the
over-the-counter market, "Business Day" shall mean any day when the principal
exchange in which securities are then listed or admitted to trading is open for
trading or, if such securities are traded in the over-the-counter market in the
United States, such market is open for trading, and provided further that any
reference to "days" (unless Business Days are specified) shall mean calendar
days.

                  Commission: the Securities and Exchange Commission or any
other Federal agency at the time administering the Securities Act or the
Exchange Act, whichever is the relevant statute for the particular purpose.

                  Common Stock: the Company's Common Stock, as constituted on
the date hereof, any stock into which such Common Stock shall have been changed
or any stock resulting from any reclassification of such Common Stock, and all
other stock of any class or classes (however designated) of the Company the
holders of which have the right, without limitation as to amount, either to all
or to a share of the balance of current dividends and liquidating dividends
after the payment of dividends and distributions on any shares entitled to
preference.

                  Company:  the meaning specified in the opening paragraphs of
the Warrant.

                  Convertible Securities: any evidences of indebtedness, shares
of stock (other than Common Stock and Preferred Shares) or other securities
directly or indirectly convertible into or exchangeable for Additional Shares of
Common Stock.

                  Exchange Act: the Securities Exchange Act of 1934, or any
successor statute, and the rules and regulations of the Commission thereunder,
all as the same shall be in effect at the time. Reference to a particular
section of the Securities Exchange Act of 1934 shall include a reference to the
comparable section, if any, of any such successor statute.

                  Exercise Price:  the meaning specified in Section 1.1.

                  Governmental Authority: any nation or government, any state or
other political subdivision thereof, and any entity, authority or body
exercising executive,

                                       18

<PAGE>

legislative, judicial, regulatory or administrative functions of or pertaining
to government.

                  Holder:  the meaning specified in Section 1.1.

                  Initial Exercise Shares: the meaning specified in the opening
paragraphs of the Warrant.

                  Investment Agreement: the meaning specified in the opening
paragraphs of the Warrant.

                  Issuance Date: the meaning specified in the opening paragraphs
of the Warrant.

                  Market Price: on any date specified herein, (a) in the case of
securities that have an existing public trading market, the amount per security
equal to (i) the average of the last sale price of such security, regular way,
for the five (5) consecutive trading days selected by the Company commencing not
more than ten (10) trading days before, and ending not later than the earlier of
the day in question and the day before the "ex" date with respect to the
issuance or distribution requiring such computation (the five (5) trading days
so selected by the Company, the "Trading Period"), or, if no such sale takes
place during such period, the average of the closing bid and asked prices
thereof during the Trading Period, in each case as officially reported on the
principal national securities exchange on which the same are then listed or
admitted to trading, or (ii) if no such security is then listed or admitted to
trading on any national securities exchange but such security is designated as a
national market system security by the NASD, the average of the last sale price
of such security, regular way, during the Trading Period, or if such security is
not so designated, the average of the reported closing bid and asked prices
thereof during the Trading Period as shown by the NASD automated quotation
system or, if no shares thereof are then quoted in such system, as published by
the National Quotation Bureau, Incorporated or any successor organization, and
in either case as reported by any member firm of the New York Stock Exchange
selected by the Company, and (b) in the case of securities that do not have an
existing public trading market and in the case of other property, the higher of
(i) the book value thereof as determined by agreement between the Company and
the Holder, or if the Company and the Holder fail to agree, by any firm of
independent public accountants of recognized standing selected by the Board of
Directors of the Company, as of the last day of any month ending within sixty
(60) days preceding the date as of which the determination is to be made and
(ii) the fair value thereof (w) determined by an agreement between the Company
and the Holder or (x) if the Company and the Holder fail to agree, determined
jointly by an independent investment banking firm retained by the Company and by
an independent investment banking firm retained by the Holder, either of which
firms may be an independent investment banking firm regularly retained by the
Company or the

                                       19

<PAGE>

Holder or (y) if the Company or the Holder shall fail so to retain an
independent investment banking firm within five Business Days of the retention
of such firm by the Holders or the Company, as the case may be, determined
solely by the firm so retained or (z) if the firms so retained by the Company
and by such holders shall be unable to reach a joint determination within
fifteen (15) Business Days of the retention of the last firm so retained,
determined by another independent investment banking firm chosen by the first
two such firms and which is not a regular investment banking firm of the Company
or any such holder.

                  NASD:  the National Association of Securities Dealers, Inc.

                  Other Securities: any stock (other than Common Stock) and
other securities of the Company or any other Person (corporate or otherwise)
which the Holder at any time shall be entitled to receive, or shall have
received, upon the exercise of the Warrant, in lieu of or in addition to Common
Stock, or which at any time shall be issuable or shall have been issued in
exchange for or in replacement of Common Stock or other securities pursuant to
Section 2.8 or otherwise.

                  Person: an individual, a partnership, an association, a joint
venture, a corporation, a limited liability company, a business, a trust, an
unincorporated organization or a government or any department, agency or
subdivision thereof.

                  Public Offering: any offering of Common Stock to the public
pursuant to an effective registration statement under the Securities Act.

                  Purchaser: the meaning specified in the first paragraph of the
Warrant.

                  Registration Rights Agreement means that certain Registration
Rights Agreement, dated as of May 21, 1998, among the Company and Clayton,
Dubilier & Rice Fund V Limited Partnership ("Fund V") and the other parties
thereto, as amended by Amendment No. 1 to the Registration Rights Agreement,
dated as of May 23, 2000, among the Company, Fund V and Clayton, Dubilier & Rice
Fund VI Limited Partnership ("Fund VI"), as further amended by Amendment No. 2
to the Registration Rights Agreement, dated as of January 15, 2002, among the
Parent, Fund V and Fund VI, and as further amended by Amendment No. 3 to the
Registration Rights Agreement, dated as of August 5, 2002, among the Parent,
Fund V, Fund VI and the Purchaser, as the same may be amended from time to time.

                  Requirement of Law: as to any Person, the Certificate of
Incorporation and By-Laws or other organizational or governing documents of such
Person, and any law, treaty, rule or regulation or determination of an
arbitrator or a court or other Governmental Authority, in each case applicable
to or binding upon such Person or any of its property or to which such Person or
any of its property is subject; provided that the

                                       20

<PAGE>

foregoing shall not apply to any non-binding recommendation of any Governmental
Authority.

                  Restricted Securities: (a) any Warrants bearing the applicable
legend set forth in Section 6, (b) any shares of Common Stock (or Other
Securities) which have been issued upon the exercise of Warrants and which are
evidenced by a certificate or certificates bearing the applicable legend set
forth in such section, and (c) unless the context otherwise requires, any shares
of Common Stock (or Other Securities) which are at the time issuable upon the
exercise of Warrants and which, when so issued, shall be evidenced by a
certificate or certificates bearing the applicable legend set forth in such
section.

                  Securities Act: the Securities Act of 1933, or any successor
statute, and the rules and regulations of the Commission thereunder, all as the
same shall be in effect at the time. Reference to a particular section of the
Securities Act of 1933 shall include a reference to the comparable section, if
any, of any such successor statute.

                  Subsidiary: as to any Person, any corporation at least a
majority of the shares of stock of which having general voting power under
ordinary circumstances to elect a majority of the Board of Directors of such
corporation (irrespective of whether or not at the time stock of any other class
or classes shall have or might have voting power by reason of the happening of
any contingency) is, at the time as of which the determination is being made,
owned by such Person, or one or more of its Subsidiaries or by such Person and
one or more of its Subsidiaries.

                  Transaction:  the meaning specified in Section 2.8.

                  Voting Securities: at any time shares of any class of capital
stock of the Company which are then entitled to vote generally in the election
of directors.

                  Warrant: the meaning specified in the second paragraph of the
Warrant.

                  Warrant Price:  the meaning specified in Section 2.1.

                  Warrant Shares: the shares of Common Stock (and Other
Securities) issuable upon exercise of the Warrant.

                  13. Remedies. The Company stipulates that the remedies at law
of the Holder in the event of any default or threatened default by the Company
in the performance of or compliance with any of the terms of the Warrant are not
and shall not be adequate and that, to the fullest extent permitted by law, such
terms may be specifically enforced by a decree for the specific performance of
any agreement contained herein or by an injunction against a violation of any of
the terms hereof or otherwise.

                                       21

<PAGE>

                  14. No Rights or Liabilities as Shareholder. Nothing contained
in the Warrant shall be construed as conferring upon the Holder hereof any
rights as a shareholder of the Company or as imposing any liabilities on such
Holder to purchase any securities or as a shareholder of the Company, whether
such liabilities are asserted by the Company or by creditors or shareholders of
the Company or otherwise.

                  15. Notices. All notices and other communications under the
Warrant, except notices of the exercise of any Warrant (which shall be effected
in the manner provided in Section 1), shall be in writing and shall be mailed by
registered or certified mail, return receipt requested, addressed as follows or
to such other address as such party may have designated to the other in writing:

                  (a)   if to the Purchaser, to it at:

                           CD&R VI (Barbados) Ltd.
                           c/o Corporate Services Limited
                           The Financial Services Centre
                           Bishop's Court Hill
                           St. Michael, Barbados

                           Attention:  Janelle Ifill
                           Telecopy No.:  (246) 436-7057

                  with a copy to:

                           Clayton, Dubilier & Rice, Inc.
                           375 Park Avenue
                           New York, New York  10152

                           Attention:  Richard J. Schnall
                           Telecopy No.:  (212) 407-7042

                  with a copy to:

                           Debevoise & Plimpton
                           919 Third Avenue
                           New York, New York  10022

                           Attention:  Paul S. Bird
                           Telecopy No.:  (212) 909-6836

                                       22

<PAGE>

                  (b) if to any other Holder or any holder of any Common Stock
(or Other Securities), at the registered address of such Holder as set forth in
the register kept at the principal office of the Company,

                           or

                  (c) if to the Company, to it at:

                           Acterna Corporation
                           20410 Observation Drive
                           Germantown, Maryland  20876

                           Attention:  General Counsel
                           Telecopy No.:  (301) 353-0740

                  16. Severability. If any term, provision, covenant or
restriction of the Warrant is held by a court of competent jurisdiction to be
invalid, void or unenforceable, the remainder of the terms, provisions,
covenants and restrictions of the Warrant shall remain in full force and effect
and shall in no way be affected, impaired or invalidated.

                  17. Miscellaneous. The Warrant and any term hereof may be
changed, waived, discharged or terminated only by an instrument in writing
signed by the party against which enforcement of such change, waiver, discharge
or termination is sought. The agreements of the Company contained in the Warrant
other than those applicable solely to the Warrant and the Holder thereof shall
inure to the benefit of and be enforceable by any Holder or Holders at the time
of any shares of Common Stock (or Other Securities) issued upon the exercise of
the Warrant, whether so expressed or not. THE WARRANT SHALL BE CONSTRUED AND
ENFORCED IN ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF NEW YORK
(WITHOUT GIVING EFFECT TO ITS PRINCIPLES OR RULES OF CONFLICT OF LAWS TO THE
EXTENT SUCH PRINCIPLES OR RULES WOULD REQUIRE OR PERMIT THE APPLICATION OF THE
LAWS OF ANOTHER JURISDICTION). EACH PARTY HEREBY IRREVOCABLY SUBMITS TO THE
EXCLUSIVE JURISDICTION OF THE COURTS OF THE STATE OF NEW YORK AND THE FEDERAL
COURTS OF THE UNITED STATES OF AMERICA LOCATED IN THE STATE OF NEW YORK SOLELY
IN RESPECT OF THE INTERPRETATION AND ENFORCEMENT OF THE PROVISIONS OF THIS
WARRANT. EACH PARTY HEREBY WAIVES AND AGREES NOT TO ASSERT, AS A DEFENSE IN ANY
ACTION, SUIT OR PROCEEDING FOR THE INTERPRETATION AND ENFORCEMENT HEREOF, THAT
SUCH ACTION, SUIT OR PROCEEDING MAY NOT BE BROUGHT OR IS NOT MAINTAINABLE IN
SUCH COURTS OR THAT THE VENUE THEREOF MAY NOT BE APPROPRIATE OR THAT THIS
WARRANT

                                       23

<PAGE>

MAY NOT BE ENFORCED IN OR BY SUCH COURTS. EACH PARTY HEREBY CONSENTS TO AND
GRANTS ANY SUCH COURT JURISDICTION OVER THE PERSON OF SUCH PARTIES AND OVER THE
SUBJECT MATTER OF ANY SUCH DISPUTE AND AGREES THAT THE MAILING OF PROCESS OR
OTHER PAPERS IN CONNECTION WITH ANY SUCH ACTION OR PROCEEDING IN ANY MANNER
PERMITTED BY LAW, SHALL BE VALID AND SUFFICIENT SERVICE THEREOF. The section
headings in the Warrant are for purposes of convenience only and shall not
constitute a part hereof.

                              ACTERNA CORPORATION

                              By:   ______________________________________
                                    Name:
                                    Title:

                                       24

<PAGE>

                              FORM OF SUBSCRIPTION

                 (To be executed only upon exercise of Warrant)

To:  Acterna Corporation

                  The undersigned registered holder of the within Warrant hereby
irrevocably exercises such Warrant for, and purchases thereunder, ________/1/
shares of Common Stock of Acterna Corporation, and herewith makes payment [of
$  ]/2/ [by application, pursuant to Section 1.1(b) of such Warrant, of [a
portion of] the Warrant representing a right to purchase ________/1/ shares of
Common Stock],/3/ and requests that the certificates for such shares be issued
in the name of, and delivered to _____________ whose address is _______________.

Dated:
                                    [HOLDER]/4/
                                    [Address]

                              By    ______________________________________
                                    Name:
                                    Title:

__________
/1/  Insert here the number of shares called for on the face of the Warrant (or,
in the case of a partial exercise, the portion thereof as to which the Warrant
is being exercised), in either case without making any adjustment for additional
Common Stock or any other stock or other securities or property or cash which,
pursuant to the adjustment provisions of the Warrant, may be delivered upon
exercise. In the case of a partial exercise, a new Warrant or Warrants shall be
issued and delivered, representing the unexercised portion of the Warrant, to
the holder surrendering the same.
/2/  Delete inapplicable language in brackets.
/3/  Delete inapplicable language in brackets.
/4/  Signature must conform in all respects to name of holder as specified on
the face of the Warrant.

                                       25

<PAGE>

                               FORM OF ASSIGNMENT

                 (To be executed only upon transfer of Warrant)

                  For value received, the undersigned registered holder of the
within Warrant hereby sells, assigns and transfers unto ________________ the
right represented by such Warrant to purchase ______ shares of Common Stock of
Acterna Corporation to which such Warrant relates, and appoints ___________
Attorney to make such transfer on the books of the Company maintained for such
purpose, with full power of substitution in the premises.

Dated:
                                    [HOLDER]/5/
                                    [Address]

                              By    ______________________________________
                                    Name:
                                    Title:

Signed in the presence of:

___________________________________

___________
/5/  Signature must conform in all respects to name of holder as specified on
the face of the Warrant.

                                       26<PAGE>

                                                                    Exhibit 4.16

                                 FIRST AMENDMENT

                  FIRST AMENDMENT, dated as of August 5, 2002 (this
"Amendment"), to the Investment Agreement, dated as of December 27, 2001 (as
amended, supplemented or otherwise modified, the "Investment Agreement"), among
Acterna Corporation, a Delaware corporation (together with its successors and
assigns, the "Parent"), Acterna LLC, a Delaware limited liability company wholly
owned and controlled by the Parent (together with its successors and assigns,
the "Company") and Clayton, Dubilier & Rice Fund VI Limited Partnership, a
Cayman Islands exempted limited partnership (together with its successors and
assigns, the "Investor").

                              W I T N E S S E T H:

                  WHEREAS, pursuant to the Investment Agreement, the Investor
has purchased certain 12% Senior Secured Convertible Notes due December 31, 2007
of the Company;

                  WHEREAS, in connection with a proposed purchase by CD&R VI
(Barbados), Ltd. of the Senior Secured Convertible Notes due December 31, 2007,
Series 2 of the Company, the Company and the Parent have requested the Investors
to agree to amend the Investment Agreement; and

                  WHEREAS, the Investor has agreed to the requested amendments
but only on the terms and conditions contained in this Amendment;

                  NOW, THEREFORE, the parties hereto hereby agree as follows:

                  Section 1. Defined Terms. Terms defined in the Investment
Agreement and used herein shall have the meanings given to them in the
Investment Agreement.

                  Section 2. Amendment to Subsection 6.6 (Mandatory Offer to
Repurchase the CD&R Notes Upon Disposition of Assets). Section 6.6(a) of the
Investment Agreement is hereby amended by deleting the parenthetical "(other
than to the Company or any of its Restricted Subsidiaries)" where it appears in
clause (i) of the definition of Mandatory 6.6(a) Repurchase Event and inserting
in lieu thereof the parenthetical "(other than to the Company or any of its
Restricted Subsidiaries, and other than any sale, transfer or other disposition
described in subsection 14.5(m) of the Credit Agreement as amended by the Third
Credit Agreement Amendment, to the extent the proceeds thereof are used in
accordance with the Credit Agreement as so amended)".

                  Section 3. Amendment to Section 7.10 (Liens). Section 7.10 of
the Investment Agreement is hereby amended by inserting the phrase "other than
Airshow Sale Proceeds Cash Collateral Account (as defined in the Credit
Agreement as amended by the Third Credit Agreement Amendment)" immediately after
the phrase "properties or assets" in such Section 7.10.

                  Section 4. Amendment to Section 8.2 (Limitation on Restricted
Payments). Section 8.2(a) of the Investment Agreement is hereby amended by
inserting at the end of the parenthetical in clause (iii), and at the end of the
first parenthetical in clause (iv), of such Section

<PAGE>

8.2(a) the phrase "and other than as permitted by Section 14.12 of the Credit
Agreement as amended by the Third Credit Agreement Amendment".

                  Section 5. Amendment to Section 8.7 (Limitation on Optional
Payments and Modifications of Debt Instruments and other Material Agreements).
Section 8.7 of the Investment Agreement is hereby amended by inserting at the
beginning of clause (a) of such Section 8.7 the phrase "except as permitted by
Section 14.12(a) of the Credit Agreement as amended by the Third Credit
Agreement Amendment,".

                  Section 6. Amendment to Section 8.8 (Limitation on Negative
Pledge Clauses). Section 8.8 of the Investment Agreement is hereby amended by
inserting in clause (a) of such Section 8.8 immediately after the phrase "this
Agreement and the other Note Financing Documents" the phrase ", the Barbados
Investment Agreement and any Note Financing Documents as defined in the Barbados
Investment Agreement".

                  Section 7. Amendment to Section 10.1 (Events of Default).
Section 10.1(f) of the Investment Agreement is hereby amended by deleting the
phrase "or (ii)" in such Section 10.1(f) and inserting in lieu thereof the
phrase ", (ii) any Barbados Default Event shall occur or exist or (iii)".

                  Section 8. Amendment to Article XII (Definitions). (a) Article
XII of the Investment Agreement is hereby amended by adding the following new
definitions in the appropriate alphabetical order:

                           "Barbados Default Event" means a "Default" or "Event
                  of Default" as those terms are defined in the Barbados
                  Investment Agreement, or any other default or event of default
                  under the Barbados Investment Agreement.

                           "Barbados Investment Agreement" means the Investment
                  Agreement, dated as of August 5, 2002, among the Company, the
                  Parent and CD&R VI (Barbados), Ltd., as the same may be
                  amended, supplemented, waiver or otherwise modified from time
                  to time.

                           "Barbados Notes" means the "Notes" as defined in the
                  Barbados Investment Agreement.

                           "Third Credit Agreement Amendment" means the Third
                  Amendment, dated as of August 7, 2002, to the Credit
                  Agreement.

                  (b) Article XII of the Investment Agreement is hereby further
amended by deleting the phrase "or (4)" where it occurs in clause (k) of the
definition of "Permitted Liens" and inserting in lieu thereof the phrase ", (4)
securing the Barbados Notes or (5)" in clause (p) of the definition of
"Permitted Liens."

                  (c) Article XVIII of the Investment Agreement is hereby
amended by adding the following provision as Section 13.17 of the Investment
Agreement:

                                        2

<PAGE>

                           "Limitation on Certain Transactions. The Investor
                  hereby agrees that, from and after the date hereof, neither
                  the Investor nor any other investment vehicle managed by
                  Clayton, Dubilier & Rice, Inc. shall engage in any Rule 13e-3
                  transaction, as such term is defined in Rule 13e-3 of the
                  Exchange Act, without the prior written consent of the Special
                  Committee (as such term is defined in the Barbados Investment
                  Agreement). The agreements in this Section 13.17 shall survive
                  repayment of the Notes and all other amounts payable hereunder
                  and the issuance of the Warrants."

                  Section 9. Amendments to Guarantee and Collateral Agreement.
The definition of "Credit Agreement" in Section 1.1 of the Guarantee and
Collateral Agreement is hereby amended by deleting "2001" and inserting in lieu
thereof "2000".

                  Section 10. Consent. The Investor hereby consents to the
amendment contained in the Third Credit Agreement Amendment to Section 14.12(e)
of the Credit Agreement.

                  Section 11. Waiver. In furtherance of the foregoing, the
Investor consents to the Company's and the Parent's execution, delivery and
performance of the Investment Agreement, dated as of the date of this Amendment,
among the Company, the Parent and CD&R VI (Barbados), Ltd., and hereby waives
any default or event of default under the Investment Agreement or the other Note
Financing Documents that may result from such execution, delivery or
performance.

                  Section 12. Representation and Warranties; No Defaults or
Events of Default. Each of the Company and the Parent represents and warrants to
the Administrative Agent and the Lenders that as of the date hereof, after
giving effect to this Amendment, no Default or Event of Default has occurred and
is continuing, and the representations and warranties made by the Company and
the Parent in or pursuant to the Investment Agreement or any other Note
Financing Document are true and correct in all material respects on and as of
the date hereof as if made on such date (except to the extent of changes
resulting from transactions contemplated or permitted by this Amendment, and
except to the extent that any such representations and warranties expressly
relate to an earlier date, in which case such representations and warranties
were true and correct in all material respects on and as of such earlier date).

                  Section 13. Payment of Expenses. The Company agrees to pay or
reimburse the Investor for all of its reasonable out-of-pocket costs and
expenses incurred in connection with this Amendment, any other documents
prepared in connection herewith and the transactions contemplated hereby,
including, without limitation, the reasonable fees and disbursements of counsel
to the Investor.

                  Section 14. Continuing Effect of the Investment Agreement.
This Amendment shall not constitute an amendment or waiver of or consent to any
provision of the Investment Agreement not expressly referred to herein and shall
not be construed as an amendment, waiver or consent to any action on the part of
the Parent or the Company or any of its Subsidiaries that would require an
amendment, waiver or consent of the Investor except as expressly stated herein.
Except as expressly amended hereby, the provisions of the Investment Agreement
are and shall remain in full force and effect in accordance with its terms.

                                       3

<PAGE>

                  Section 15. Counterparts. This Amendment may be executed by
one or more of the parties to this Amendment on any number of separate
counterparts (including by facsimile), and all of said counterparts taken
together shall be deemed to constitute one and the same instrument.

                  Section 16. GOVERNING LAW. THIS AMENDMENT AND THE RIGHTS AND
OBLIGATIONS OF THE PARTIES UNDER THIS AMENDMENT SHALL BE GOVERNED BY, AND
CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.

            [The remainder of this page is intentionally left blank.]

                                       4

<PAGE>

                  IN WITNESS WHEREOF, the parties hereto have caused this
Amendment to be duly executed and delivered by their respective proper and duly
authorized officers as of the day and year first above written.

                                    ACTERNA LLC

                                    By: __________________________________
                                          Name:
                                          Title:

                                    ACTERNA CORPORATION

                                    By: ____________________________________
                                          Name:
                                          Title:

                                    CLAYTON, DUBILIER & RICE FUND VI
                                     LIMITED PARTNERSHIP

                                    By: CD&R Associates VI Limited Partnership,
                                     its general partner

                                    By: CD&R Investment Associates VI, Inc., its
                                     managing general partner

                                    By: ____________________________________
                                          Name:
                                          Title:

<PAGE>

                           ACKNOWLEDGMENT AND CONSENT

         Each of the undersigned as guarantors under the Guarantee and
Collateral Agreement, dated as of December 27, 2001, made by the undersigned in
favor of the Investor and the other Secured Parties referred to therein, hereby
(a) consents to the transactions contemplated by this Amendment and (b)
acknowledges and agrees that the guarantees (and grants of collateral security
therefor) contained in such Guarantee and Collateral Agreement are, and shall
remain, in full force and effect after giving effect to this Amendment.

                                    ACTERNA BUSINESS TRUST

                                    By: ____________________________________
                                          Name:
                                          Title:

                                    Airshow, Inc.

                                    By: ____________________________________
                                          Name:
                                          Title:

                                    APPLIED DIGITAL ACCESS, INC.

                                    By: ____________________________________
                                          Name:
                                          Title:

                                    DA VINCI SYSTEMS, INC.

                                    By: ____________________________________
                                          Name:
                                          Title:

<PAGE>

                                    ITRONIX CORPORATION

                                    By: ____________________________________
                                          Name:
                                          Title:

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