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                                                                   EXHIBIT 10.21

                           FOOTWEAR ACQUISITION, INC.
                         591 Redwood Highway, Suite 2180
                          Mill Valley, California 94941
                                       USA

                                                                   April 5, 2001

UNION OVERSEAS HOLDINGS LIMITED

            Re: Sourcing Rights with Union Overseas Holdings Limited

Dear Sirs:

      We refer to the Stock and Note Purchase Agreement between Footwear
Acquisition Inc. ("Footwear"), yourselves ("UOHL") and certain other
stockholders identified therein dated April 5, 2001 (the "SPA") and the related
Investors Rights Agreement between the same parties dated the same date (the
"IRA").

      In connection with our purchase of the assets of Converse, Inc. and your
purchase of certain of our capital stock pursuant to the SPA, we have agreed to
provide certain footwear product sourcing rights as set forth below, and
accordingly, the parties acknowledge and agree as follows:

      1. All capitalized terms used but not otherwise defined herein shall have
the same meanings as are ascribed thereto in the SPA or the IRA, as indicated
below.

      2. The terms of this Letter Agreement shall become effective immediately
prior to the closing under the APA.

      3. If UOHL meets Footwear's good faith requirements as to price, quality
and delivery, Footwear will purchase its good faith footwear requirements from
UOHL, or any direct or indirect subsidiary of Symphony Holdings Ltd.
("Symphony") or any other corporate Affiliate of Symphony (collectively, the
"Manufacturer"). Footwear products for which Manufacturer meets Footwear's good
faith requirements as to price, quality and delivery are referred to as
"Qualified Products."

      4. With respect to Footwear's requirements for footwear products that are
not Qualified Products ("Non-Qualified Products"), Footwear shall in good faith
provide (i) to the extent practicable or permitted (based on trade secret and
patent limitations) the requirements and specifications for such Non-Qualified
Products and (ii) Manufacturer a commercially reasonable opportunity to
manufacture a portion of such requirements. To the extent Footwear does not
purchase its requirement for Non-Qualified Products from Manufacturer after
Manufacturer has requested an opportunity to do so, Footwear shall deliver a
good faith written notification to Manufacturer of the basis for such decision.
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      5. The price and other terms for Footwear's purchase of products shall be
commercially reasonable, taking into account price, other market terms then
prevailing and Footwear's good faith requirements.

      6. In respect of Qualified Products, the parties recognize that Footwear
may secure alternative second source suppliers on a commercially prudent basis.
For example, Footwear may protect against natural disaster and political risks
and over-concentration in manufacturing activities with Manufacturer in respect
to a specific footwear style. In no event, however, shall Footwear purchase 50%
or more of its footwear requirements for Qualified Products from any such second
source.

      7. Footwear shall form a research and development operating committee
(which shall be maintained to consider Footwear's research and development needs
and direction) and Manufacturer shall have the right to designate a
representative to serve on such committee.

      8. Within 30 days of the date hereof, the parties shall negotiate in good
faith the terms and methods for the (i) placement of orders, (ii) payment for
orders, (iii) determination of purchase prices, (iv) shipping methods and (v)
such other details as are necessary to carry out the terms of this Letter
Agreement.

      9. Each party agrees to carry out in good faith its obligations with
respect to this Letter Agreement.

      10. Unless sooner terminated pursuant to the provisions of the second
sentence of this paragraph 10, this letter agreement shall continue for seven
years from date of the closing under the APA, and shall automatically renew for
successive one year terms (each such one year term, a "Renewal Term"), unless
one party delivers to the other party notice of nonrenewal at least 180 days
prior to the expiration any Renewal Term. Notwithstanding the foregoing, this
Letter Agreement shall immediately terminate and be of no further force and
effect (i) if UOHL holds less than 50% of the shares of Common Stock it owned
immediately following the closing under the SPA, (ii) upon the occurrence of a
Change in Control of Footwear (as defined in the IRA), (iii) upon the
commencement of a Qualified Initial Public Offering (as defined in the IRA) if
such Qualified Initial Public Offering occurs after 42 months after the closing
under the APA; or (iv) 42 months after the closing under the APA if such
Qualified Initial Public Offering occurs prior to the 42nd month after the
closing under the APA.

      11. Miscellaneous

            (a) Any term of this Letter Agreement may be amended or waived only
with the written consent of the parties to this Letter Agreement.

            (b) This Letter Agreement shall be governed by the laws of the State
of New York.

            (c) All notices, requests and other communications hereunder shall
be in writing and shall be delivered in accordance with the SPA.

            (d) This Letter Agreement may be executed in any number of
counterparts, each of which shall be an original, but all of which together
shall constitute one instrument.
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This Agreement, the agreements referred to herein, and each other agreement or
instrument entered into in connection herewith or therewith or contemplated
hereby or thereby, and any amendments hereto or thereto, to the extent signed
and delivered by means of a facsimile machine, shall be treated in all manners
and respects as an original agreement or instrument and shall be considered to
have the same binding legal effect as if it were the original signed version
thereof delivered in person. At the request of any party hereto or to any such
agreement or instrument, each other party hereto or thereto shall re-execute
original forms thereof and deliver them to all other parties. No party hereto or
to any such agreement or instrument shall raise the use of a facsimile machine
to deliver a signature or the fact that any signature or agreement or instrument
was transmitted or communicated through the use of a facsimile machine as a
defense to the formation or enforceability of a contract and each such party
forever waives any such defense.

                                                   FOOTWEAR ACQUISITION, INC.

                                                   By: /s/ William N. Simon
                                                       Name: William N. Simon
                                                       Title: Executive Director

AGREED AND ACCEPTED AS OF THE DATE SET
FORTH ABOVE:

UNION OVERSEAS HOLDINGS LIMITED

By: /s/ Edward D. Sy
    Name: Edward D. Sy
    Title: Director<PAGE>

                                                                    EXHIBIT 10.4

                                 THIRD AMENDMENT
                                       TO
                            ZOLL MEDICAL CORPORATION
                             1992 STOCK OPTION PLAN

      WHEREAS, the ZOLL Medical Corporation 1992 Stock Option Plan (the "Plan")
was adopted by the Board of Directors and the stockholders of ZOLL Medical
Corporation (the "Company") on April 22, 1992 as a performance incentive for
officers, employees, consultants and other key persons of the Company;

      WHEREAS, Section 3(a) of the Plan provides that the total number of shares
of the Company's common stock, $.02 par value per share (the "Common Stock"),
which may be issued pursuant to stock options granted under the Plan shall not
exceed an aggregate of 450,000 shares of Common Stock;

      WHEREAS, an amendment to the Plan authorizing the issuance of an
additional 300,000 shares of Common Stock pursuant to the Plan was approved by
the Board of Directors of the Company on November 14, 1994 and was thereafter
approved by the stockholders of the Company on January 30, 1995 (the "First
Amendment");

      WHEREAS, an amendment to the Plan authorizing the issuance of an
additional 200,000 shares of Common Stock was approved by the Board of Directors
on November 21, 1996 and thereafter approved by the stockholders of the Company
on February 4, 1997 (the "Second Amendment");

      WHEREAS, the Board of Directors of the Company believes that the number of
shares of Common Stock remaining available for issuance under the Plan has
become insufficient for the Company's current and anticipated future needs;

      WHEREAS, Section 10 of the Plan provides that the Board of Directors of
the Company may amend the Plan at any time, subject to certain conditions set
forth therein; and

      WHEREAS, the Board of Directors of the Company has determined that it is
in the best interests of the Company to amend the Plan to provide that an
additional 300,000 shares of Common Stock be made available for issuance under
the Plan.

      NOW, THEREFORE:

      1.    Amendment of Plan. Section 3(a) of the Plan is hereby amended and
restated to provide in its entirety as follows:

            (a)   The stock granted under the Plan, or subject to the options
                  granted under the Plan, shall be shares of the Company's
                  authorized but unissued common stock, par value $.02 per share
                  (the "Common Stock"). The total number of shares that may be
                  issued under the Plan shall not exceed an aggregate of
                  1,250,000 shares of Common Stock. Such number shall be subject
                  to adjustment as provided in Section 7 hereof.

      2.    Effective Date of Amendment. This Third Amendment to the Plan shall
become effective upon the date that it is adopted by the Board of Directors of
the Company; provided, however, that this Third Amendment shall be subject to
the approval of the Company's stockholders in accordance with applicable laws
and regulations at an annual or special meeting held within twelve months of
such effective date. No stock option granted under the Plan prior to such
stockholder approval may be exercised to the extent that the number of shares of
Common Stock then available for issuance under the Plan, without giving effect
to this Third Amendment, shall be less than the number of shares of Common Stock
proposed to be purchased pursuant to such exercise.
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      IN WITNESS WHEREOF, this Third Amendment to the Plan has been adopted by
the Board of Directors of the Company this 19th day of November, 1998, to be
submitted for approval by the Company's stockholders at the Company's Annual
Meeting of Stockholders to be held on February 4, 1999.

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