<PAGE>

                          AMENDMENT TO RIGHTS AGREEMENT



      THIS AMENDMENT TO THE RIGHTS AGREEMENT (the "Amendment") is entered into
as of the 30th day of August, 2001, by and between BEI MEDICAL SYSTEMS COMPANY,
INC. (f/k/a BEI Electronics, Inc.), a Delaware corporation (the "Company") and
the MELLON INVESTOR SERVICES, LLC (f/k/a ChaseMellon Shareholder Services,
L.L.C.) (the "Rights Agent"), parties to that certain Rights Agreement, entered
into as of June 30, 1997 (the "Agreement"). Capitalized terms used in this
Amendment and not otherwise defined herein shall have the meanings given them in
the Agreement.

      WHEREAS, Section 27 of the Agreement provides that the Company and the
Rights Agent shall, if the Company so directs, supplement or amend any provision
of the Agreement without the approval of any holders of the Rights, any such
supplement or amendment to be evidenced by a writing signed by the Company and
the Rights Agent;

      WHEREAS, the Company desires to amend the Agreement to add Brookside
Capital Partners Fund, L.P. to the definition of "Excluded Person," and the
Company's Board of Directors has approved such amendment;

      WHEREAS, pursuant to Section 27 of the Agreement, the Company has
delivered to the Rights Agent a certificate signed by the Chief Executive
Officer of the Company certifying that the proposed amendment of the Agreement
is in compliance with the terms of Section 27 of the Agreement;

      NOW, THEREFORE, in consideration of the promises and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties mutually agree:

      1.    AMENDMENT. Section 1(h) of the Agreement is amended in its entirety
to read as follows:

                  (H)   "EXCLUDED PERSON" shall mean (1) Charles Crocker so long
                        as he beneficially owns 30% or less of the outstanding
                        Common Shares or (2) Brookside Capital Partners Fund,
                        L.P. so long as it beneficially owns 30% or less of the
                        outstanding Common Shares; provided, however, that
                        Charles Crocker shall not be an Excluded Person if he
                        beneficially owns more than 30% of the outstanding
                        Common Shares without the prior approval of the Board of
                        Directors of the Company.

      2.    MISCELLANEOUS

                                       1.
<PAGE>

                  (A)   GOVERNING LAW. This Amendment shall be deemed to be a
contract made under the laws of the State of Delaware and for all purposes shall
be governed by and construed in accordance with the laws of such State
applicable to contracts to be made and performed entirely within such State.

                  (B)   COUNTERPARTS. This Amendment may be executed in several
counterparts, each of which shall constitute an original and all of which, when
taken together, shall constitute one agreement.

                  (C)   TITLES AND SUBTITLES. The titles and subtitles used in
this Amendment are for convenience only and are not to be considered in
construing or interpreting this Amendment.


      The foregoing AMENDMENT TO THE RIGHTS AGREEMENT is hereby executed and
consented to as of the date first above written.

COMPANY:                                 RIGHTS AGENT:

BEI MEDICAL SYSTEMS COMPANY, INC.        MELLON INVESTOR SERVICES, LLC

By: /a/ R.W. Turner                      By: /s/ Nathan Hill
    --------------------------------         -----------------------------------
Name:  R.W. Turner                       Name: Nathan Hill
       -----------------------------           ---------------------------------
Title:  President & CEO                  Its: Assistant Vice President
        ----------------------------          ----------------------------------

                                       2.