<PAGE>
 
                                                                     EXHIBIT 4.8


--------------------------------------------------------------------------------

                          PERSEPTIVE BIOSYSTEMS, INC.



                                      AND



                    AMERICAN STOCK TRANSFER & TRUST COMPANY



                                AS RIGHTS AGENT



                                   __________



                                RIGHTS AGREEMENT



                           DATED AS OF MARCH 1, 1995


--------------------------------------------------------------------------------
<PAGE>
 
                               TABLE OF CONTENTS
                               -----------------



SECTION                                                                 PAGE
-------                                                                 ----

     1.  Certain Definitions...........................................   7

     2.  Appointment of Rights Agent...................................  12

     3.  Issue of Rights Certificates..................................  12

     4.  Form of Rights Certificates...................................  14

     5.  Countersignature and Registration.............................  15

     6.  Transfer, Split Up, Combination and
         Exchange of Rights Certificates; Mutilated,
         Destroyed, Lost or
         Stolen Rights Certificates....................................  15

     7.  Exercise of Rights; Purchase Price;
         Expiration Date of Rights.....................................  16

     8.  Cancellation and Destruction of Rights Certificates...........  18

     9.  Reservation and Availability of Capital Stock.................  18

    10.  Preferred Stock Record Date...................................  19

    11.  Adjustment of Purchase Price, Number and Kind of Shares or
          Number of Rights.............................................  20

    12.  Certificate of Adjusted Purchase Price or
         Number of Shares..............................................  28

    13.  Consolidation, Merger or Sale or Transfer of
          Assets or Earning Power......................................  28

    14.  Fractional Rights and Fractional Shares.......................  30

    15.  Rights of Action..............................................  31

    16.  Agreement of Rights Holders...................................  32

    17.  Rights Certificate Holder Not Deemed a Stockholder............  32

    18.  Concerning the Rights Agent...................................  33

    19.  Merger or Consolidation or Change of
         Name of Rights Agent..........................................  33

    20.  Duties of Rights Agent........................................  34

    21.  Change of Rights Agent........................................  35

    22.  Issuance of New Rights Certificates...........................  36
<PAGE>
 
    23.  Redemption and Termination...................................   37

    24.  Exchange.....................................................   38

    25.  Notice of Certain Events.....................................   39

    26.  Notices......................................................   40

    27.  Supplements and Amendments...................................   40

    28.  Successors...................................................   41

    29.  Determinations and Actions by the Board of Directors, etc....   41

    30.  Benefits of this Agreement...................................   42

    31.  Severability.................................................   42

    32.  Governing Law................................................   42

    33.  Counterparts.................................................   42

    34.  Descriptive Headings.........................................   42


Exhibit A --  Form of Certificate of Designation of Preferred Stock

Exhibit B --  Form of Rights Certificate


Exhibit C --  Form of Summary of Rights
<PAGE>
 
                                RIGHTS AGREEMENT
                                ----------------



          RIGHTS AGREEMENT, dated as of March 1, 1995 (the "Agreement"), between
                                                            ---------           
PERSEPTIVE BIOSYSTEMS, INC., a Delaware corporation (the "Company"), and
                                                          -------       
AMERICAN STOCK TRANSFER & TRUST COMPANY, as Rights Agent (the "Rights Agent").
                                                               ------------   



                                   WITNESSETH



          WHEREAS, on February 23, 1995 (the "Rights Dividend Declaration
                                              ---------------------------
Date"), the Board of Directors of the Company (the "Board") authorized and
                                                    -----                 
declared a dividend distribution of one Right for each share of Common Stock (as
hereinafter defined) of the Company outstanding at the close of business on
March 2, 1995 (the "Record Date"), and has authorized the issuance of one Right
                    -----------                                                
(as such number may hereinafter be adjusted pursuant to the provisions of
Section 11(a)(i) hereof) for each share of Common Stock of the Company issued
(whether originally issued or delivered from the Company's treasury) between the
Record Date and the Distribution Date, each Right initially representing the
right to purchase one one-hundredth of a share of Series B Junior Participating
Preferred Stock upon the terms and conditions hereinafter set forth (the
                                                                        
"Rights");
 ------   

          NOW, THEREFORE, in consideration of the premises and the mutual
agreements herein set forth, the parties hereby agree as follows:

          Section 1.  Certain Definitions. For purposes of this Agreement,
                      -------------------
the following terms have the meanings indicated:

                (a)  "Acquiring Person" shall mean any Person who or which,
                      ----------------  
together with all Affiliates and Associates of such Person, shall be the
Beneficial Owner of 15% or more of the shares of Common Stock then outstanding,
but shall not include the Company, any Subsidiary of the Company, any employee
benefit plan of the Company or of any Subsidiary of the Company, or any Person
or entity organized, appointed or established by the Company for or pursuant to
the terms of any such plan. Notwithstanding the foregoing, no Person shall
become an "Acquiring Person" as the result of an acquisition of Common Stock by
the Company which, by reducing the number of shares outstanding, increases the
proportionate number of shares beneficially owned by such Person to 15% or more
of the Common Stock of the Company then outstanding; provided, however, that if
                                                     --------  -------         
a Person shall become the Beneficial Owner of 15% or more of the Common Stock of
the Company then outstanding by reason of share purchases by the Company and
shall, after such share purchases by the Company, become the Beneficial Owner of
any additional Common Stock of the Company, then such Person shall be deemed to
be an "Acquiring Person."  Notwithstanding the foregoing, if the Board, with the
consent of a majority of the Continuing Directors, determines in good faith that
a Person who would otherwise be an "Acquiring Person," as defined pursuant to
the foregoing provisions of this paragraph (a), has become such inadvertently,
and such Person divests as promptly as practicable a sufficient number of
shares of Common Stock so that such Person would no longer be an "Acquiring
Person," as defined pursuant to the foregoing provisions of this paragraph (a),
then such Person shall not be deemed to be an "Acquiring Person" for any
purposes of this Agreement. In addition, and notwithstanding the foregoing, any
Person who, together with any Affiliates or Associates of such Person, shall
become the Beneficial Owner of 15% or more of the shares of 

<PAGE>
 
Common Stock then outstandingas a result of a transaction or series of
transactions involving the redemption, conversion, exchange or cancellation of
some or all of the outstanding shares of the Company's Series A Redeemable
Convertible Preferred Stock, $.01 par value per share, shall not be deemed to be
an "Acquiring Person" for any purposes of this Agreement if such transaction or
series of transactions has been approved in advance by a majority of the
Continuing Directors.

                (b)  "Act" shall mean the Securities Act of 1933, as amended.
                      ---            

                (c) "Adjustment Shares" shall have the meaning set forth
                     -----------------
in Section 11(a)(ii)(D) hereof.

                (d) "Adverse Person" shall mean any Person declared to be an 
                     --------------                                       
Adverse Person by the Continuing Directors upon determination that the criteria
set forth in Section 11(a)(ii)(D) hereof apply to such Person.

                (e) "Adverse Person Event" shall mean the determination by the
                     --------------------                                     
Continuing Directors (with the concurrence of the Independent Directors),
pursuant to Section 11(a)(ii)(D) hereof, that a Person is an Adverse Person.

                (f) "Affiliate" and "Associate" shall have the respective 
                     ---------       ---------         
meanings ascribed to such terms in Rule 12b-2 of the General Rules and
Regulations under the Securities Exchange Act of 1934, as amended and in effect
on the date of this Agreement (the "Exchange Act").
                                    ------------   

                (g) "Agreement" shall mean this Rights Agreement as originally
                     ---------                                                
executed or as it may from time to time be supplemented or amended pursuant to
the applicable provisions hereof.

                (h) A Person shall be deemed the "Beneficial Owner and shall
                                                  ----------------
be deemed to "beneficially own", any securities:

                (i)   which such Person or any of such Person's Affiliates or
                      Associates, directly or indirectly, has the right to
                      acquire (whether such right is exercisable immediately or
                      only after the passage of time) pursuant to any agreement,
                      arrangement or understanding, whether or not in writing,
                      or upon the exercise of conversion rights, exchange
                      rights, other rights, warrants or options, or otherwise;
                      provided, however, that a Person shall not be deemed the
                      --------  -------                     
                      "Beneficial Owner" of, or to "beneficially own", (A)
                      securities tendered pursuant to a tender offer or exchange
                      offer made by such Person or any of such Person's
                      Affiliates or Associates until such tendered securities
                      are accepted for purchase or exchange, or (B) securities
                      issuable upon exercise of Rights at any time prior to the
                      occurrence of a Triggering Event, or (C) securities
                      issuable upon exercise of Rights from and after the
                      occurrence of a Triggering Event which Rights were
                      acquired by such Person or any of such Person's Affiliates
                      or Associates prior to the Distribution Date or pursuant
                      to Section 3(a) or Section 22 hereof (the "Original
                                                                 --------
                      Rights") or pursuant to Section 11(a)(i) hereof in
                      ------ 
                      connection with an adjustment made with respect to any
                      Original Rights;
<PAGE>
 
                (ii)  which such Person or any of such Person's Affiliates or
                      Associates, directly or indirectly, has the right to vote
                      or dispose of or has "beneficial ownership" of (as
                      determined pursuant to Rule 13d-3 of the General Rules and
                      Regulations under the Exchange Act, or any comparable or
                      successor rule), including pursuant to any agreement,
                      arrangement or understanding, whether or not in writing;
                      provided, however, that a Person shall not be deemed the
                      --------  ------- 
                      "Beneficial Owner" of, or to "beneficially own", any
                      security under this subparagraph (ii) as a result of an
                      agreement, arrangement or understanding to vote such
                      security if such agreement, arrangement or understanding:
                      (A) arises solely from a revocable proxy given in response
                      to a public proxy or consent solicitation made pursuant
                      to, and in accordance with, the applicable provisions of
                      the General Rules and Regulations under the Exchange Act,
                      and (B) is not also then reportable by such Person on
                      Schedule 13D under the Exchange Act (or any comparable or
                      successor report); or

                (iii) which are beneficially owned, directly or indirectly, by
                      any other Person (or any Affiliate or Associate thereof)
                      with which such Person (or any of such Person's Affiliates
                      or Associates) has any agreement, arrangement or
                      understanding, whether or not in writing, for the purpose
                      of acquiring, holding, voting (except pursuant to a
                      revocable proxy as described in the proviso to
                      subparagraph (ii) of this paragraph (h)) or disposing of
                      any voting securities of the Company (a joint filing of a
                      Schedule 13D under the Exchange Act or any comparable or
                      successor report being deemed to be conclusive evidence of
                      such an agreement, arrangement or understanding);
                      provided, however, that nothing in this paragraph (h) 
                      --------  ------- 
                      shall cause a Person engaged in business as an underwriter
                      of securities to be the "Beneficial Owner" of, or to
                      "beneficially own", any securities acquired through such
                      Person's participation in good faith in a firm commitment
                      underwriting until the expiration of forty days after the
                      date of such acquisition.

          Notwithstanding anything in this definition of Beneficial Ownership to
the contrary, the phrase "then outstanding," when used with reference to a
Person's Beneficial Ownership of securities of the Company, shall mean the
number of such securities then issued and outstanding together with the number
of such securities not then actually issued and outstanding which such Person
would be deemed to own beneficially hereunder.

                (i) "Board" means the Board of Directors of the Company.
                     -----       

                (j) "Business Day" shall mean any day other than a Saturday, 
                     ------------                          
Sunday or a day on which banking institutions in the State of New York are
authorized or obligated by law or executive order to close.

                (k) "Close of Business" on any given date shall mean 5:00 P.M.,
                    ------------------
New York time, on such date; provided, however, that if such date is not a 
                             --------  -------    
Business Day it shall mean 5:00 P.M., New York time, on the next succeeding
Business Day.
<PAGE>
 
                (l) "Common Stock" shall mean the common stock, $.01 par value
                     ------------                    
per share, of the Company, except that "Common Stock" when used with reference
to any Person other than the Company shall mean the capital stock of such Person
with the greatest voting power, or the equity securities or other equity
interest having power to control or direct the management, of such Person.

                (m) "Common Stock Equivalents" shall have the meaning
                     ------------------------
set forth in Section 11(a)(iii) hereof.

                (n) "Company" shall mean the Person named as the "Company" in 
                     -------         
the first paragraph of this Agreement until a successor corporation shall have
become such or until a Principal Party shall assume, and thereafter be liable
for, all obligations and duties of the Company hereunder, pursuant to the
applicable provisions of this Agreement, and thereafter "Company" shall mean
such successor corporation or Principal Party.

                (o) "Continuing Director" shall mean (i) any member of the 
                     -------------------       
Board, while such Person is a member of the Board, who is not an Acquiring
Person or an Adverse Person, or an Affiliate or Associate of such Person, or a
representative of such Person or of any such Affiliate or Associate, and was a
member of the Board on the date of this Agreement, or (ii) any Person who
becomes a member of the Board subsequent to the date of this Agreement, while
such Person is a member of the Board, who is not an Acquiring Person or an
Adverse Person, or an Affiliate or Associate of such Person, or a representative
of an Acquiring Person or an Adverse Person or of any such Affiliate or
Associate, if such Person's nomination for election or election to the Board is
recommended or approved by a majority of the Continuing Directors.

                (p) "Current Market Price" shall have the meaning set forth
                     --------------------
in Section 11(d)(i) hereof.

                (q) "Current Value" shall have the meaning set forth
                     ------------- 
in Section 11(a)(iii) hereof.

                (r) "Distribution Date" shall have the meaning set forth in
                     -----------------
Section 3(a) hereof.

                (s) "Equivalent Preferred Stock" shall have the meaning set
                     --------------------------
forth in Section 11(b) hereof.
                
                (t) "Exchange Act" shall have the meaning set forth in
                     ------------ 
Section 1(f) hereof.

                (u) "Expiration Date" shall have the meaning set forth
                     ---------------
in Section 7(a) hereof.

                (v) "Final Amendment Date" shall mean the earlier of the 
                     --------------------      
Distribution Date or the occurrence of an Adverse Person Event.

                (w) "Final Expiration Date" shall mean the close of
                      ---------------------
business on March 2, 2005.

                (x) "Independent Directors" shall mean the Continuing Directors
                     ---------------------
who are not executive officers of the Company.
<PAGE>
 
                (y) "Initial Exercise Price" shall be $47.00.
                     ----------------------

                (z) "Nasdaq" shall mean the National Association of Securities
                     ------       
Dealers, Inc. Automated Quotation System.

                (aa) "Original Rights" shall have the meaning set forth
                      ---------------
in Section 1(h)(i) hereof.

                (bb) "Person" shall mean any natural person, firm, association,
                      ------                                                   
corporation, partnership, trust or other entity or organization.

                (cc) "Preferred Stock" shall mean the Series B Junior  
                      ---------------        
Participating Preferred Stock, $.01 par value per share, of the Company having
the terms set forth in the form of certificate of designation attached hereto as
Exhibit A.
--------- 
                (dd) "Principal Party" shall have the meaning set forth
                      ---------------
in Section 13(b) hereof.

                (ee) "Purchase Price" shall have the meaning set forth
                      --------------
in Section 4(a) hereof.

                (ff) "Record Date" shall have the meaning set forth in the
                      ----------- 
preamble of the Agreement.

                (gg) "Redemption Price" shall have the meaning set forth
                      ----------------
in Section 23(a) hereof.

                (hh) "Rights" shall have the meaning set forth in the
                      ------       
preamble of the Agreement.

                (ii) "Rights Agent" shall mean the Person named as the "Rights
                      ------------                               
Agent" in the first paragraph of this Agreement until a successor Rights Agent
shall have become such pursuant to the applicable provisions hereof, and
thereafter "Rights Agent" shall mean such successor Rights Agent. If at any time
there is more than one Person appointed by the Company as Rights Agent pursuant
to the applicable provisions of this Agreement, "Rights Agent" shall mean and
include each such Person.

                (jj) "Rights Certificates" shall have the meaning set forth
                      -------------------
in Section 3(a) hereof.

                (kk) "Rights Dividend Declaration Date" shall have the
                      --------------------------------
meaning set forth in the preamble of this Agreement.

                (ll) "Section 11(a)(ii) Event" shall mean any event
                      -----------------------
described in Section 11(a)(ii)(A), (B), (C) or (D) hereof.

                (mm) "Section 11(a)(ii) Trigger Date" shall have the
                      ------------------------------
meaning set forth in Section 11(a)(iii) hereof.

                (nn) "Section 13 Event" shall mean any event described
                      ----------------
in clauses (x), (y) or (z) of Section 13(a) hereof.
<PAGE>
 
                (oo) "Spread" shall have the meaning set forth in Section
                      ------       
 11(a)(iii) hereof.

                (pp) "Stock Acquisition Date" shall mean the first date of a 
                      ----------------------            
public announcement (which, for purposes of this definition, shall include,
without limitation, a report filed pursuant to Section 13(d) under the Exchange
Act) by the Company or an Acquiring Person that an Acquiring Person has become
such.

                (qq) "Subsidiary" shall mean, with reference to any Person, 
                      ----------        
including the Company, any corporation of which an amount of voting securities
sufficient to elect at least a majority of the directors of such corporation is
beneficially owned, directly or indirectly, by such Person, or which is
otherwise controlled by such Person.

                (rr) "Substitute Consideration" shall have the meaning set
                      ------------------------
forth in Section 11(a)(iii) hereof.

                (ss) "Substitution Period" shall have the meaning set forth
                      -------------------
in Section 11(a)(iii) hereof.

                (tt) "Trading Day" shall have the meaning set forth in
                      ----------- 
Section 11(d) hereof.

                (uu) "Triggering Event" shall mean any Section 11(a)(ii)
                      ----------------
Event or any Section 13 Event.

        Section 2. Appointment of Rights Agent.   The Company hereby appoints
                   ---------------------------
the Rights Agent to act as agent for the Company and the holders of the Rights
(who, in accordance with Section 3 hereof, shall prior to the Distribution Date
also be the holders of the Common Stock) in accordance with the terms and
conditions hereof, and the Rights Agent hereby accepts such appointment. The
Company may from time to time appoint such Co-Rights Agents as it may deem
necessary or desirable.

        Section 3.  Issue of Rights Certificates.
                    ----------------------------
                (a) Until the earliest of (i) the Close of Business on the tenth
day after the Stock Acquisition Date (or, if the tenth day after the Stock
Acquisition Date occurs before the Record Date, the Close of Business on the
Record Date), (ii) the Close of Business on the tenth Business Day (or, if such
tenth Business Day occurs before the Record Date, the Close of Business on the
Record Date), or such specified or unspecified later date on or after the Record
Date as may be determined by action of a majority of the Continuing Directors,
after the date that a tender offer or exchange offer by any Person (other than
the Company, any Subsidiary of the Company, any employee benefit plan of the
Company or of any Subsidiary of the Company, or any Person or entity organized,
appointed or established by the Company for or pursuant to the terms of any such
plan) is first published or sent or given within the meaning of Rule 14d-2(a) of
the General Rules and Regulations under the Exchange Act, if upon consummation
thereof for the maximum number of shares that may be purchased thereunder, such
Person would be the Beneficial Owner of 15% or more of the shares of Common
Stock then outstanding or (iii) the Close of Business on the tenth Business Day
after an Adverse Person Event (the earliest of (i), (ii) and (iii) being herein
referred to as the "Distribution Date"), (x) the Rights will be evidenced
                    -----------------                                    
(subject to the provisions of paragraph (b) of this Section 3) by the
certificates for the Common Stock registered in the names of the holders of the
Common Stock (which certificates for Common Stock shall be deemed also to be
certificates for Rights) and not by separate certificates, and 
<PAGE>
 
(y) the Rights will be transferable only in connection with the transfer of the
underlying shares of Common Stock (including a transfer to the Company). As soon
as practicable after the Distribution Date, the Rights Agent will send by first-
class, insured, postage prepaid mail, to each record holder of the Common Stock
as of the Close of Business on the Distribution Date, at the address of such
holder shown on the records of the Company, one or more rights certificates, in
the form specified in Section 4 hereof (the "Rights Certificates"), evidencing
                                             -------------------              
one Right for each share of Common Stock so held, subject to adjustment as
provided herein.  In the event that an adjustment in the number of Rights per
share of Common Stock has been made pursuant to Section 11(a)(i) hereof, at the
time of distribution of the Rights Certificates, the Company shall make the
necessary and appropriate rounding adjustments (in accordance with Section 14(a)
hereof) so that Rights Certificates representing only whole numbers of Rights
are distributed and cash is paid in lieu of any fractional rights.  As of and
after the Distribution Date, the Rights will be evidenced solely by such Rights
Certificates.

          (b) As promptly as practicable following the Record Date, the Company
will send a copy of a Summary of Rights, in substantially the form attached
hereto as Exhibit C, by first-class, postage prepaid mail, to each record holder
          ---------                                                             
of the Common Stock as of the Close of Business on the Record Date, at the
address of such holder shown on the records of the Company. With respect to
certificates for the Common Stock outstanding as of the Record Date, until the
Distribution Date, the Rights will be evidenced by such certificates for the
Common Stock and the registered holders of the Common Stock shall also be the
registered holders of the associated Rights. Until the earlier of the
Distribution Date or the Expiration Date (as such term is defined in Section 7
hereof), the transfer of any certificates representing shares of Common Stock in
respect of which Rights have been issued shall also constitute the transfer of
the Rights associated with such shares of Common Stock.

          (c) Rights shall be issued in respect of all shares of Common Stock
that are issued (whether originally issued or from the Company's treasury) after
the Record Date but prior to the earlier of the Distribution Date or the
Expiration Date.  Rights shall also be issued to the extent provided in Section
22 in respect of all shares of Common Stock which are issued (whether originally
issued or from the Company's treasury) after the Distribution Date and prior to
the Expiration Date.  Certificates representing such shares of Common Stock in
respect of which Rights are issued pursuant to the first sentence of this
Section 3(c) shall also be deemed to be certificates for Rights, and commencing
as soon as reasonably practicable following the date hereof shall bear the
following legend:

       This certificate also evidences and entitles the holder hereof to certain
       Rights as set forth in the Rights Agreement between PerSeptive
       Biosystems, Inc. (the "Company") and American Stock Transfer & Trust
       Company (the "Rights Agent") dated as of March 1, 1995 (the "Rights
       Agreement"), the terms of which are hereby incorporated herein by
       reference and a copy of which is on file at the principal offices of the
       Company.  Under certain circumstances, as set forth in the Rights
       Agreement, such Rights will be evidenced by separate certificates and
       will no longer be evidenced by this certificate.  The Company will mail
       to the holder of this certificate a copy of the Rights Agreement, as in
       effect on the date of mailing, without charge promptly after receipt of a
       written request therefor.  Under certain circumstances set forth in the
       Rights Agreement, Rights issued to, or held by, any Person who is, was or
       becomes an Acquiring Person, an Adverse Person or any Affiliate or
       Associate of an Acquiring Person or an Adverse Person (as such terms are
       defined in the 
<PAGE>
 
       Rights Agreement), whether currently held by or on behalf of such Person
       or by any subsequent holder, may become null and void. The Rights shall
       not be exercisable, and shall be void so long as held, by a holder in any
       jurisdiction where the requisite qualification to the issuance to such
       holder, or the exercise by such holder, of the Rights in such
       jurisdiction shall not have been obtained or obtainable.

With respect to such certificates containing the foregoing legend, until the
earlier of (i) the Distribution Date or (ii) the Expiration Date, the Rights
associated with the Common Stock represented by such certificates shall be
evidenced by such certificates alone and registered holders of Common Stock
shall also be the registered holders of the associated Rights, and the transfer
of any of such certificates shall also constitute the transfer of the Rights
associated with the Common Stock represented by such certificates.

        Section 4.  Form of Rights Certificates.
                    ---------------------------

                (a) The Rights Certificates (and the forms of election to
purchase and of assignment to be printed on the reverse thereof) shall each be
substantially in the form set forth in Exhibit B hereto and may have such marks
                                       --------- 
of identification or designation and such legends, summaries or endorsements
printed thereon as the Company may deem appropriate and as are not inconsistent
with the provisions of this Agreement, or as may be required to comply with any
applicable law or with any rule or regulation made pursuant thereto or with any
rule or regulation of any stock exchange or trading market on which the Rights
may from time to time be listed, or to conform to usage. Subject to the
provisions of Section 11 and Section 22 hereof, the Rights Certificates,
whenever distributed, shall be dated as of the Record Date and on their face
shall entitle the holders thereof to purchase such number of one one-hundredths
of a share of Preferred Stock as shall be set forth therein at the price per
share set forth therein (such exercise price per one one-hundredth of a share
hereinafter referred to as the "Purchase Price"), but the amount and type of
                                --------------                              
securities purchasable upon the exercise of each Right and the Purchase Price
thereof shall be subject to adjustment as provided herein.

          (b) Any Rights Certificate issued pursuant to Section 3(a) or Section
22 hereof that represents Rights beneficially owned by:  (i) an Acquiring
Person, an Adverse Person or any Associate or Affiliate of an Acquiring Person
or an Adverse Person, (ii) a transferee of an Acquiring Person or an Adverse
Person (or of any such Associate or Affiliate of an Acquiring Person or an
Adverse Person) who becomes a transferee after the Acquiring Person or Adverse
Person becomes such, or (iii) a transferee of an Acquiring Person or an Adverse
Person (or of any such Associate or Affiliate of an Acquiring Person or an
Adverse Person) who becomes a transferee prior to or concurrently with the
Acquiring Person or the Adverse Person becoming such and receives such Rights
pursuant to either (A) a transfer (whether or not for consideration) from the
Acquiring Person or the Adverse Person to holders of equity interests in such
Acquiring Person or Adverse Person or to any Person with whom such Acquiring
Person or Adverse Person has any continuing agreement, arrangement or
understanding regarding the transferred Rights or (B) a transfer which a
majority of the Continuing Directors has determined is part of a plan,
arrangement or understanding that has as a primary purpose or effect avoidance
of Section 7(e) hereof, and any Rights Certificate issued pursuant to Section 6
or Section 11 hereof upon transfer, exchange, replacement or adjustment of any
other Rights Certificate referred to in this sentence, shall contain (to the
extent feasible) the following legend:

       The Rights represented by this Rights Certificate are or were
       beneficially 
<PAGE>
 
       owned by a Person who was or became an Acquiring Person, Adverse Person,
       or an Affiliate or Associate of an Acquiring Person or Adverse Person (as
       such terms are defined in the Rights Agreement). Accordingly, this Rights
       Certificate and the Rights represented hereby may become null and void in
       the circumstances specified in Section 7(e) of such Agreement.

       Section 5. Countersignature and Registration
                  ---------------------------------

          (a) The Rights Certificates shall be executed on behalf of the Company
by its President or any Vice President, either manually or by facsimile
signature, and shall have affixed thereto the Company's seal or a facsimile
thereof which shall be attested by the Secretary or an Assistant Secretary of
the Company, either manually or by facsimile signature.  The Rights Certificates
shall be manually countersigned by the Rights Agent and shall not be valid for
any purpose unless so countersigned.  In case any officer of the Company who
shall have signed any of the Rights Certificates shall cease to be such officer
of the Company before countersignature by the Rights Agent and issuance and
delivery by the Company, such Rights Certificates, nevertheless, may be
countersigned by the Rights Agent and issued and delivered by the Company with
the same force and effect as though the person who signed such Rights
Certificates had not ceased to be such officer of the Company; and any Rights
Certificates may be signed on behalf of the Company by any person who, at the
actual date of the execution of such Rights Certificate, shall be a proper
officer of the Company to sign such Rights Certificate, although at the date of
the execution of this Rights Agreement any such person was not such an officer.

          (b) Following the Distribution Date, the Rights Agent will keep or
cause to be kept, at its principal office or offices designated as the
appropriate place for surrender of Rights Certificates upon exercise or
transfer, books for registration and transfer of the Rights Certificates issued
hereunder.  Such books shall show the names and addresses of the respective
holders of the Rights Certificates, the number of Rights evidenced on its face
by each of the Rights Certificates, the Rights Certificate number and the date
of each of the Rights Certificates.

          Section 6.  Transfer, Split Up, Combination and Exchange of Rights
                      ------------------------------------------------------
Certificates; Mutilated, Destroyed, Lost or Stolen Rights Certificates.
----------------------------------------------------------------------

          (a) Subject to the provisions of Section 4(b), Section 7(e) and
Section 14 hereof, at any time after the Close of Business on the Distribution
Date, and at or prior to the Close of Business on the Expiration Date, any
Rights Certificate or Certificates may be transferred, split up, combined or
exchanged for another Rights Certificate or Certificates, entitling the
registered holder to purchase a like number of one one-hundredths of a share of
Preferred Stock (or, following a Triggering Event, Common Stock, other
securities, cash or other assets, as the case may be) as the Rights Certificate
or Certificates surrendered then entitled such holder (or former holder in the
case of a transfer) to purchase.  Any registered holder desiring to transfer,
split up, combine or exchange any Rights Certificate or Certificates shall make
such request in writing delivered to the Rights Agent, and shall surrender the
Rights Certificate or Certificates to be transferred, split up, combined or
exchanged at the office of the Rights Agent designated for such purpose.
Neither the Rights Agent nor the Company shall be obligated to take any action
whatsoever with respect to the transfer of any such surrendered Rights
Certificate or Certificates until the registered holder shall have completed and
signed the certificate contained in the form of assignment set forth on the
reverse side of each such Rights Certificate and shall have provided such
additional evidence of the identity of the
Beneficial Owner (or former Beneficial Owner) or Affiliates or Associates
thereof as the Company shall reasonably request.  Thereupon 
<PAGE>
 
the Rights Agent shall, subject to Section 4(b), Section 7(e) and Section 14
hereof, countersign and deliver to the Person entitled thereto a Rights
Certificate or Certificates, as the case may be, as so requested. The Company
may require payment of a sum sufficient to cover any tax or governmental charge
that may be imposed in connection with any transfer, split up, combination or
exchange of Rights Certificates.

          (b) Upon receipt by the Company and the Rights Agent of evidence
reasonably satisfactory to them of the loss, theft, destruction or mutilation of
a Rights Certificate, and, in case of loss, theft or destruction, of indemnity
or security reasonably satisfactory to them, and reimbursement to the Company
and the Rights Agent of all reasonable expenses incidental thereto, and upon
surrender to the Rights Agent and cancellation of the Rights Certificate if
mutilated, the Company will execute and deliver a new Rights Certificate of like
tenor to the Rights Agent for countersignature and delivery to the registered
owner in lieu of the Rights Certificate so lost, stolen, destroyed or mutilated.

        Section 7.  Exercise of Rights; Purchase Price; Expiration Date of 
                    ------------------------------------------------------
Rights.
------

        (a) Subject to Section 7(e) hereof, the registered holder of any
Rights Certificate may exercise the Rights evidenced thereby (except as
otherwise provided herein including, without limitation, the restrictions set
forth in Section 9(c), Section 11(a)(iii) and Section 23(a) hereof) in whole or
in part at any time after the Distribution Date upon surrender of the Rights
Certificate, with the form of election to purchase set forth on the reverse side
thereof and the certificate contained therein completed and duly executed, to
the Rights Agent at the office of the Rights Agent designated for such purpose,
together with payment of the aggregate Purchase Price with respect to the total
number of one one-hundredths of a share of Preferred Stock (or other securities,
cash or other assets, as the case may be) as to which such surrendered Rights
are then exercisable, at or prior to the earlier of (i) the Final Expiration
Date, (ii) the time at which the Rights are redeemed as provided in Section 23
hereof, (iii) the time at which the Rights expire pursuant to Section 13(d)
hereof or (iv) the time at which such Rights are exchanged as provided in
Section 24 hereof (the earliest of (i), (ii), (iii) or (iv) being herein
referred to as the "Expiration Date").
                    ---------------   

        (b) The Purchase Price for each one one-hundredth of a share of
Preferred Stock pursuant to the exercise of a Right shall initially be the
Initial Exercise Price, and shall be subject to adjustment from time to time as
provided in Sections 11 and 13(a) hereof and shall be payable in accordance with
paragraph (c) below.

        (c) Upon receipt of a Rights Certificate representing exercisable
Rights, with the form of election to purchase set forth on the reverse side
thereof and the certificate contained therein completed and duly executed,
accompanied by payment, with respect to each Right so exercised, of the Purchase
Price per one one-hundredth of a share of Preferred Stock (or other securities,
cash or other assets, as the case may be) to be purchased as set forth below and
an amount equal to any applicable transfer tax, the Rights Agent shall, subject
to Section 20(k) hereof, promptly (i) requisition from any
transfer agent of the shares of Preferred Stock (or make available, if the
Rights Agent is the transfer agent for such shares) certificates for the total
number of one one-hundredths of a share of Preferred Stock to be purchased and
the Company hereby irrevocably authorizes its transfer agent to comply with all
such requests, (ii) requisition from the Company the amount of cash, if any, to
be paid in lieu of fractional shares in accordance with Section 14 hereof, (iii)
after receipt of such certificates, cause the same to be delivered to or upon
the order of the registered holder of such Rights Certificate, registered in
such name or names as 
<PAGE>
 
may be designated by such holder, and (iv) after receipt thereof, deliver such
cash, if any, to or upon the order of the registered holder of such Rights
Certificate. The payment of the Purchase Price (as such amount may be reduced
pursuant to Section 11(a)(iii) hereof) shall be made in cash or by certified
check, cashier's check or bank draft payable to the order of the Company. In the
event that the Company is obligated to issue other securities (including Common
Stock) of the Company, pay cash or distribute other property pursuant to Section
11(a) hereof, the Company will make all arrangements necessary so that such
other securities, cash or other property are available for distribution by the
Rights Agent, if and when appropriate. The Company reserves the right to require
prior to the occurrence of a Triggering Event that, upon any exercise of Rights,
such number of Rights be exercised so that only whole shares of Common Stock
would be issued.

          (d) In case the registered holder of any Rights Certificate shall
exercise less than all the Rights evidenced thereby, a new Rights Certificate
evidencing the Rights equivalent to the Rights remaining unexercised shall be
issued by the Rights Agent and delivered to, or upon the order of, the
registered holder of such Rights Certificate, registered in such name or names
as may be designated by such holder, subject to the provisions of Section 14
hereof.

          (e) Notwithstanding anything in this Agreement to the contrary, from
and after the first occurrence of an event described in Section 11(a)(ii)(A) or
(C) and from and after the Close of Business on the tenth day after the
occurrence of an event described in Section 11(a)(ii)(B) or (D), any Rights
beneficially owned by (i) an Acquiring Person, an Adverse Person or an Associate
or Affiliate of an Acquiring Person or Adverse Person, which a majority of the
Continuing Directors, in their sole discretion, determines is or was involved in
or caused or facilitated, directly or indirectly (including through any change
in the Board), such Section 11(a)(ii) Event, (ii) a transferee of any such
Acquiring Person or Adverse Person (or of any such Associate or Affiliate of an
Acquiring Person or an Adverse Person) who becomes a transferee after such
Acquiring Person or Adverse Person becomes such, or (iii) a transferee of any
such Acquiring Person or Adverse Person (or of any such Associate or Affiliate
of an Acquiring Person or an Adverse Person) who becomes a transferee prior to
or concurrently with such Acquiring Person or Adverse Person becoming such and
receives such Rights pursuant to either (A) a transfer (whether or not for
consideration) from such Acquiring Person or Adverse Person to holders of equity
interests in such Acquiring Person or Adverse Person or to any Person with whom
such Acquiring Person or Adverse Person has any continuing agreement,
arrangement or understanding regarding the transferred Rights or (B) a transfer
which a majority of the Continuing Directors has determined is part of a plan,
arrangement or understanding which has as a primary purpose or effect the
avoidance of this Section 7(e), shall become null and void without any further
action and no holder of such Rights shall have any rights whatsoever with
respect to such Rights, whether under any provision of this Agreement or
otherwise. The Company shall use all reasonable efforts to ensure that the
provisions of this Section 7(e) and Section 4(b) hereof are complied with, but
shall have no liability to any holder of Rights Certificates or other Person as
a result of its failure to make any determinations with respect to an Acquiring
Person or Adverse Person or any of their Affiliates, Associates or transferees
hereunder.

          (f) Notwithstanding anything in this Agreement to the contrary,
neither the Rights Agent nor the Company shall be obligated to undertake any
action with respect to a registered holder upon the occurrence of any purported
exercise as set forth in this Section 7 unless such registered holder shall have
(i) completed and signed the certificate contained in the form of election to
purchase set forth on the reverse side of the Rights Certificate surrendered for
such exercise, and (ii) provided such additional evidence of the identity of the
Beneficial Owner (or former Beneficial Owner) or Affiliates or Associates
thereof as the Company shall reasonably 
<PAGE>

request.
 
        Section 8. Cancellation and Destruction of Rights Certificates.
                   ---------------------------------------------------
     All Rights Certificates surrendered for the purpose of exercise, transfer,
split up, combination or exchange shall, if surrendered to the Company or any of
its agents, be delivered to the Rights Agent for cancellation or in canceled
form, or, if surrendered to the Rights Agent, shall be canceled by it, and no
Rights Certificates shall be issued in lieu thereof except as expressly
permitted by any of the provisions of this Agreement.  The Company shall deliver
to the Rights Agent for cancellation and retirement, and the Rights Agent shall
so cancel and retire, any other Rights Certificate purchased or acquired by the
Company otherwise than upon the exercise thereof.  The Rights Agent shall
deliver all canceled Rights Certificates to the Company, or shall, at the
written request of the Company, destroy such canceled Rights Certificates, and
in such case shall deliver a certificate of destruction thereof to the Company.

        Section 9. Reservation and Availability of Capital Stock.
                   ---------------------------------------------

                (a) The Company covenants and agrees that it will cause to be
reserved and kept available out of its authorized and unissued shares of
Preferred Stock (and, following the occurrence of a Triggering Event, out of its
authorized and unissued shares of Common Stock or other securities or out of its
authorized and issued shares held in its treasury), the number of shares of
Preferred Stock (and, following the occurrence of a Triggering Event, Common
Stock or other securities) that, as provided in this Agreement including Section
11(a)(iii) hereof, will be sufficient to permit the exercise in full of all
outstanding Rights.

                (b) So long as the shares of Preferred Stock (and, following the
occurrence of a Triggering Event, Common Stock or other securities) issuable and
deliverable upon the exercise of the Rights may be listed on any national
securities exchange, the Company shall use its best efforts to cause all shares
reserved for such issuance to be listed on such exchange upon official notice of
issuance upon such exercise.

                (c) The Company shall use its best efforts to (i) file, as soon
as practicable following the earliest date after the first occurrence of a
Triggering Event in which the consideration to be delivered by the Company upon
exercise of the Rights has been determined in accordance with this Agreement, a
registration statement under the Act, with respect to the Common Stock or other
securities purchasable upon exercise of the Rights on an appropriate form, (ii)
cause such registration statement to become effective as soon as practicable
after such filing, and (iii) cause such registration statement to remain
effective (with a prospectus at all times meeting the requirements of the Act)
until the earlier of (A) the date as of which the Rights are no longer
exercisable for such securities, and (B) the Expiration Date. The Company will
also take such action as may be appropriate under, or to ensure compliance with,
the securities or "blue sky" laws of the various states in connection with the
exercisability of the Rights. The Company may temporarily suspend, for a period
of time not to exceed ninety (90) days after the date set forth in clause (i) of
the first sentence of this Section 9(c), the exercisability of the Rights in
order to prepare and file such registration statement and permit it to become
effective. In addition, if the Company shall determine that a registration
statement is required following the Distribution Date, the Company may
temporarily suspend the exercisability of the Rights until such time as a
registration statement has been declared effective. Upon any suspension of the
exercisability of the Rights referred to in this Section 9(c), the Company shall
issue a public announcement stating that the exercisability of the Rights has
been temporarily suspended, as well as a public announcement at such time as the
suspension is no longer in effect. Notwithstanding any
<PAGE>
 
provision of this Agreement to the contrary, the Rights shall not be exercisable
and shall be void so long as held by a holder in any jurisdiction where the
requisite qualification to the issuance to such holder, or the exercise by such
holder, of the Rights in such jurisdiction shall not have been obtained or be
obtainable, the exercise thereof shall not be permitted under applicable law or
a registration statement shall not have been declared effective.

                (d) The Company covenants and agrees that it will take all such
action as may be necessary to ensure that all one one-hundredths of a share of
Preferred Stock (and, following the occurrence of a Triggering Event, Common
Stock or other securities) delivered upon exercise of Rights shall, at the time
of delivery of the certificates for such shares (subject to payment of the
Purchase Price), be duly and validly authorized and issued and fully paid and
nonassessable.

                (e) The Company further covenants and agrees that it will pay
when due and payable any and all federal and state transfer taxes and charges
that may be payable in respect of the issuance or delivery of the Rights
Certificates and of any certificates for a number of one one-hundredths of a
share of Preferred Stock (or Common Stock or other securities, as the case may
be) upon the exercise of Rights. The Company shall not, however, be required to
pay any transfer tax that may be payable in respect of any transfer or delivery
of Rights Certificates to a Person other than, or the issuance or delivery of a
number of one one-hundredths of a share of Preferred Stock (or Common Stock or
other securities, as the case may be) in respect of a name other than that of,
the registered holder of the Rights Certificates evidencing Rights surrendered
for exercise or to issue or deliver any certificates for a number of one one-
hundredths of a share of Preferred Stock (or Common Stock or other securities,
as the case may be) in a name other than that of the registered holder upon the
exercise of any Rights until such tax shall have been paid (any such tax being
payable by the holder of such Rights Certificates at the time of surrender) or
until it has been established to the Company's satisfaction that no such tax is
due.

        Section 10. Preferred Stock Record Date.    Each Person in whose name
                    ---------------------------
any certificate for a number of one one-hundredths of a share of Preferred Stock
(or Common Stock or other securities, as the case may be) is issued upon the
exercise of Rights shall for all purposes be deemed to have become the holder of
record of such Preferred Stock (or Common Stock or other securities, as the case
may be) represented thereby on, and such certificate shall be dated, the date
upon which the Rights Certificate evidencing such Rights was duly surrendered
and payment of the Purchase Price (and all applicable transfer taxes) was made;
provided, however, that if the date of such surrender and payment is a
--------  -------             
date upon which the Preferred Stock (or Common Stock or other securities, as the
case may be) transfer books of the Company are closed, such Person shall be
deemed to have become the record holder of such shares on, and such certificate
shall be dated, the next succeeding Business Day on which the Preferred Stock
(or other securities, as the case may be) transfer books of the Company are
open. Prior to the exercise of the Rights evidenced thereby, the holder of a
Rights Certificate shall not be entitled to any rights of a stockholder of the
Company with respect to shares for which the Rights shall be exercisable,
including, without limitation, the right to vote, to receive dividends or other
distributions or to exercise any preemptive rights, and shall not be entitled to
receive any notice of any proceedings of the Company, except as provided herein.

        Section 11. Adjustment of Purchase Price, Number and Kind of Shares 
                    -------------------------------------------------------
or Number of Rights.   The Purchase Price, the number and kind of shares covered
-------------------
by each Right and the number of Rights outstanding are subject to adjustment
from time to time as provided in this Section 11.

                (a)(i) In the event the Company shall at any time after the date
of this 
<PAGE>
 
Agreement (A) declare a dividend on the Preferred Stock payable in shares of
Preferred Stock, (B) subdivide the outstanding Preferred Stock, (C) combine the
outstanding Preferred Stock into a smaller number of shares, or (D) issue any
shares of its capital stock in a reclassification of the Preferred Stock
(including any such reclassification in connection with a consolidation or
merger in which the Company is the continuing or surviving corporation), except
as otherwise provided in this Section 11(a) and Section 7(e) hereof, the
Purchase Price in effect at the time of the record date for such dividend or of
the effective date of such subdivision, combination or reclassification, and the
number and kind of shares of Preferred Stock or capital stock, as the case may
be, issuable on such date, shall be proportionately adjusted so that if a holder
of Rights after such time were to exercise that number of Rights (or fraction
thereof) which would result in the aggregate amount of the Purchase Price
payable upon such exercise (at the Purchase Price then in effect) being equal to
the amount of the Purchase Price payable prior to such time upon exercise of a
Right, he would be entitled to receive the aggregate number and kind of shares
of Preferred Stock or other capital stock, as the case may be, which, if a Right
had been exercised immediately prior to such time and at a time when the
Preferred Stock transfer books (or other capital stock transfer books, as the
case may be) of the Company were open, he would have owned upon such exercise
and been entitled to receive by virtue of such dividend, subdivision,
combination or reclassification. If an event occurs that would require an
adjustment under both this Section 11(a)(i) and Section 11(a)(ii) hereof, the
adjustment provided for in this Section 11(a)(i) shall be in addition to, and
shall be made prior to, any adjustment required pursuant to Section 11(a)(ii)
hereof.

                (ii)  In the event:

                      (A) any Acquiring Person or any Associate or Affiliate of
any Acquiring Person, at any time after the date of this Agreement, directly or
indirectly, (1) shall merge into the Company or otherwise combine with the
Company and the Company shall be the continuing or surviving corporation of such
merger or combination and the Common Stock of the Company shall remain
outstanding and unchanged, (2) shall merge or otherwise combine with any
Subsidiary of the Company, (3) shall, in one transaction or a series of
transactions, transfer any assets to the Company or to any of its Subsidiaries
in exchange (in whole or in part) for shares of Common Stock, for shares of
other equity securities of the Company or any Subsidiary of the Company, or for
securities exercisable for or convertible into shares of equity securities of
the Company or any Subsidiary of the Company (Common Stock or otherwise) or
otherwise obtain from the Company, with or without consideration, any additional
shares of equity securities of the Company or securities exercisable for or
convertible into shares of such equity securities of the Company (other than
pursuant to a pro rata distribution to all holders of Common Stock or upon the
exercise of a convertible security of the Company or any Subsidiary of the
Company in accordance with its terms), (4) shall sell, purchase, lease,
exchange, mortgage, pledge, transfer or otherwise acquire or dispose of, in one
transaction or a series of transactions, to, from or with (as the case may be)
the Company or any of its Subsidiaries, assets on terms and conditions less
favorable to the Company than the Company would be able to obtain in arm's
length negotiations with an unaffiliated third party, other than pursuant to a
transaction set forth in Section 13(a) hereof, (5) shall sell, purchase, lease,
exchange, mortgage, pledge, transfer or otherwise acquire or dispose of in one
transaction or a series of transactions, to, from or with (as the case may be)
the Company or any of its Subsidiaries assets having an aggregate fair market
value of more than $1,000,000, other than pursuant to a transaction set forth in
Section 13(a) hereof and other than pursuant to a transaction or series of
transactions that have been approved by a majority of the Continuing Directors,
(6) shall receive any compensation from the Company or any of the Company's
Subsidiaries other than compensation for full-time employment as a regular
employee at rates in accordance with the Company's (or its Subsidiaries') past
practices, or (7) shall receive the benefit, directly or 
<PAGE>
 
indirectly (except proportionately as a stockholder and except if resulting from
a requirement of law or governmental regulation), of any loans, advances,
guarantees, pledges or other financial assistance or any tax credits or other
tax advantages provided by the Company or any of its Subsidiaries, or

          (B) any Person (other than the Company, any Subsidiary of the Company,
any employee benefit plan of the Company or of any Subsidiary of the Company, or
any Person or entity organized, appointed or established by the Company for or
pursuant to the terms of any such plan), alone or together with any Affiliates
and Associates of such Person, shall, at any time after the Rights Dividend
Declaration Date, become the Beneficial Owner of 15% or more of the shares of
Common Stock then outstanding, unless (1) the event causing the 15% threshold to
be crossed is a transaction set forth in Section 13(a) hereof, (2) is an
acquisition of shares of Common Stock pursuant to a tender offer or an exchange
offer for all outstanding shares of Common Stock at a price and on terms
determined by a majority of the Independent Directors, after receiving advice
from one or more investment banking firms, to be (a) at a price that is fair to
stockholders (taking into account all factors which such members of the Board
deem relevant including, without limitation, prices which could reasonably be
achieved if the Company or its assets were sold on an orderly basis designed to
realize maximum value) and (b) otherwise in the best interest of the Company and
its stockholders or (3) the event causing the 15% threshold to be crossed is a
transaction involving the issuance of Common Stock to a Person who is has been a
holder of shares of the Company's Series A Redeemable Convertible Preferred
Stock, $.01 par value per share, (the "Series A Preferred Stock") since a date
prior to the date of this Agreement upon the redemption, conversion, exchange or
cancellation of such shares of Series A Preferred Stock, or

          (C) during such time as there is an Acquiring Person, there shall be
any reclassification of securities (including any reverse stock split), or
recapitalization of the Company, or any merger or consolidation of the Company
with any of its Subsidiaries or any other transaction or series of transactions
involving the Company or any of its Subsidiaries (whether or not with or into or
otherwise involving an Acquiring Person), other than a transaction or
transactions to which the provisions of Section 13(a) hereof apply (whether or
not with or into or otherwise involving an Acquiring Person), which has the
effect, directly or indirectly, of increasing by more than 1% the proportionate
share of the outstanding shares of any class of equity securities of the Company
or any of its Subsidiaries which is directly or indirectly beneficially owned by
any Acquiring Person or any Associate or Affiliate of any Acquiring Person, or

          (D) a majority of the Continuing Directors shall declare any Person to
be an Adverse Person, upon a determination that such Person, alone or together
with its Affiliates and Associates, has, at any time after the Rights Dividend
Declaration Date, become the Beneficial Owner of an amount of Common Stock which
a majority of Continuing Directors determine to be substantial (which amount
shall in no event be less than 15% of the shares of Common Stock then
outstanding) and a majority of the Continuing Directors determines (with the
concurrence of a majority of the Independent Directors), after reasonable
inquiry and investigation, which may include a review of the public record
regarding such Person and any information such directors may request from such
Person and consultation with such persons as such directors shall deem
appropriate, that (1) such Beneficial Ownership by such Person is intended to
cause the Company to repurchase the Common Stock beneficially owned by such
Person or to cause pressure on the Company to take action or enter into a
transaction or series of transactions intended to provide such Person with
short-term financial gain under circumstances where such directors determine
that the best long-term interests of the Company and its stockholders would 
<PAGE>
 
not be served by taking such action or entering into such transactions or series
of transactions at that time or (2) such Beneficial Ownership is causing or is
reasonably likely to cause a material adverse impact (including, but not limited
to, impairment of relationships with customers, impairment of the Company's
ability to maintain its competitive position or impairment of the Company's
business reputation or ability to deal with government agencies) on the business
or prospects of the Company, then, immediately upon the occurrence of any event
described in Section 11(a)(ii)(A) or (C) hereof, and upon the Close of Business
ten (10) days after the occurrence of any event described in Section
11(a)(ii)(B) or (D) hereof, proper provision shall be made so that each holder
of a Right (except as provided below and in Section 7(e) hereof) shall
thereafter have the right to receive, upon exercise thereof at the then current
Purchase Price in accordance with the terms of this Agreement, in lieu of a
number of one one-hundredths of a share of Preferred Stock, such number of
shares of Common Stock of the Company as shall equal the result obtained by (x)
multiplying the then current Purchase Price by the then number of one one-
hundredths of a share of Preferred Stock for which a Right was or would have
been exercisable immediately prior to the first occurrence of a Section
11(a)(ii) Event, whether or not such Right was then exercisable, and (y)
dividing that product (which, following such first occurrence, shall thereafter
be referred to as the "Purchase Price" for each Right and for all purposes of
                       --------------                                        
this Agreement) by 50% of the Current Market Price per share of Common Stock
(determined pursuant to Section 11(d) hereof) on the date of such first
occurrence (such number of shares being referred to herein as the "Adjustment
                                                                   ----------
Shares").
------   

          (iii)  In the event that the number of shares of Common Stock which
are authorized by the Company's Amended and Restated Certificate of
Incorporation, as amended, but not outstanding or reserved for issuance for
purposes other than upon exercise of the Rights are not sufficient to permit the
exercise in full of the Rights in accordance with the foregoing subparagraph
(ii) of this Section 11(a), the Company shall (A) determine the value of the
Adjustment Shares issuable upon the exercise of a Right (the "Current Value"),
                                                              -------------   
and (B) with respect to each Right (subject to Section 7(e) hereof), make
adequate provision to substitute, upon the exercise of a Right and payment of
the applicable Purchase Price, (1) cash, (2) a reduction in the Purchase Price,
(3) Common Stock or other equity securities of the Company (including, without
limitation, shares, or units of shares, of preferred stock which the Board has
deemed to have the same value as shares of Common Stock (such shares of
preferred stock being referred to herein as "Common Stock Equivalents")), (4)
                                             ------------------------        
debt securities of the Company, (5) other assets, or (6) any combination of the
foregoing, having an aggregate value equal to the Current Value, as adjusted
(less the amount of any reduction in the Purchase Price), where such aggregate
value has been determined by the Board based upon the advice of a nationally
recognized investment banking firm selected by the Board; provided, however, if
                                                          --------  -------    
the Company shall not have made adequate provision to deliver value pursuant to
clause (B) above within thirty (30) days following the later of (x) the first
occurrence of a Section 11(a)(ii) Event and (y) the first date on which the
Company's right of redemption pursuant to Section 23(a) expires (the later of
(x) and (y) being referred to herein as the "Section 11(a)(ii) Trigger Date"),
                                             ------------------------------   
then the Company shall be obligated to deliver, upon the surrender for exercise
of a Right and without requiring payment of the Purchase Price, shares of Common
Stock (to the extent available) and then, if necessary, cash, which shares or
cash have an aggregate value equal to the Spread.  For purposes of the preceding
sentence, the term "Spread" shall mean the excess of (i) the Current Value over
                    ------                                                     
(ii) the Purchase Price.  If the number of shares of Common Stock that are
authorized by the Company's Amended and Restated Certificate of Incorporation,
as amended, but not outstanding or reserved for issuance for purposes other than
upon exercise of the Rights are not sufficient to permit the exercise in full of
any Rights and the Board with the consent of a majority of the Continuing
Directors determines in good faith that it is likely that sufficient
<PAGE>
 
additional shares of Common Stock could be authorized for issuance upon exercise
in full of the Rights, the thirty (30) day period set forth above may be
extended to the extent necessary, but not more than ninety (90) days after the
Section 11(a)(ii) Trigger Date, in order that the Company may seek stockholder
approval for the authorization of such additional shares (such thirty (30) day
period, as it may be extended, shall be referred to as the "Substitution 
                                                            ------------
Period").  To the extent that the Company determines that some action need
------                                                        
be taken pursuant to the preceding provisions of this Section 11(a)(iii), the
Company (x) shall provide, subject to Section 7(e) hereof, that such action
shall apply uniformly to all outstanding Rights, and (y) may suspend the
exercisability of the Rights until the expiration of the Substitution Period in
order to seek any authorization of additional shares or to decide the
appropriate form of distribution to be made pursuant to such provisions and to
determine the value thereof. In the event of any such suspension, the Company
shall issue a public announcement stating that the exercisability of the Rights
has been temporarily suspended, as well as a public announcement at such time as
the suspension is no longer in effect. For purposes of this Section 11(a)(iii),
the value of each Adjustment Share shall be the Current Market Price per share
of the Common Stock (as determined pursuant to Section 11(d) hereof) on the
Section 11(a)(ii) Trigger Date and the per share or per unit value of any Common
Stock Equivalent shall be deemed to equal the Current Market Price per share of
the Common Stock on such date.

          (b) In case the Company shall fix a record date for the issuance of
rights (other than the Rights), options or warrants to all holders of Preferred
Stock entitling them to subscribe for or purchase (for a period expiring within
forty-five (45) calendar days after such record date) Preferred Stock, shares
having the same rights, privileges and preferences as the shares of Preferred
Stock ("Equivalent Preferred Stock") or securities convertible into Preferred
        --------------------------                                           
Stock or Equivalent Preferred Stock at a price per share of Preferred Stock or
per share of Equivalent Preferred Stock (or having a conversion price per share,
if a security convertible into Preferred Stock or Equivalent Preferred Stock)
less than the Current Market Price per share of Preferred Stock (as determined
pursuant to Section 11(d) hereof) on such record date, the Purchase Price to be
in effect after such record date shall be determined by multiplying the Purchase
Price in effect immediately prior to such record date by a fraction, the
numerator of which shall be the number of shares of Preferred Stock outstanding
on such record date, plus the number of shares of Preferred Stock which the
aggregate offering price of the total number of shares of Preferred Stock or
Equivalent Preferred Stock (or the aggregate initial conversion price of the
convertible securities so to be offered) would purchase at such Current Market
Price, and the denominator of which shall be the number of shares of Preferred
Stock outstanding on such record date, plus the number of additional shares of
Preferred Stock or Equivalent Preferred Stock to be offered for subscription or
purchase (or into which the convertible securities so to be offered are
initially convertible).  In case such subscription price may be paid by delivery
of consideration part or all of which may be in a form other than cash, the
value of such noncash consideration shall be as determined in good faith by the
Board, whose determination shall be described in a statement filed with the
Rights Agent and shall be binding on the Rights Agent and the holders of the
Rights. Shares of Preferred Stock owned by or held for the account of the
Company shall not be deemed outstanding for the purpose of any such computation.
Such adjustment shall be made successively whenever such a record date is fixed,
and in the event that such rights, options or warrants are not so issued, the
Purchase Price shall be adjusted to be the Purchase Price which would then be in
effect if such record date had not been fixed.

          (c) In case the Company shall fix a record date for a distribution to
all holders of Preferred Stock (including any such distribution made in
connection with a consolidation or merger in which the Company is the continuing
or surviving corporation) of evidences of 
<PAGE>
 
indebtedness, cash (other than a regular quarterly or other periodic cash
dividend out of the earnings or retained earnings of the Company), assets (other
than a dividend payable in Preferred Stock, but including any dividend payable
in stock other than Preferred Stock) or subscription rights or warrants
(excluding those referred to in Section 11(b) hereof), the Purchase Price to be
in effect after such record date shall be determined by multiplying the Purchase
Price in effect immediately prior to such record date by a fraction, the
numerator of which shall be the Current Market Price per share of Preferred
Stock (as determined pursuant to Section 11(d) hereof) on such record date, less
the fair market value (as determined in good faith by the Board whose
determination shall be described in a statement filed with the Rights Agent and
shall be binding on the Rights Agent) of the portion of the cash, assets or
evidences of indebtedness so to be distributed or of such subscription rights or
warrants applicable to a share of Preferred Stock and the denominator of which
shall be such Current Market Price per share of Preferred Stock (as determined
pursuant to Section 11(d) hereof). Such adjustments shall be made successively
whenever such a record date is fixed, and in the event that such distribution is
not so made, the Purchase Price shall be adjusted to be the Purchase Price which
would have been in effect if such record date had not been fixed.

          (d) (i) For the purpose of any computation hereunder, other than
computations made pursuant to Section 11(a)(iii) hereof, the Current Market
Price per share of Common Stock on any date shall be deemed to be the average of
the daily closing prices per share of such Common Stock for the thirty (30)
consecutive Trading Days immediately prior to such date, and for the purposes of
computations made pursuant to Section 11(a)(iii) hereof, the Current Market
Price per share of Common Stock on any date shall be deemed to be the average of
the daily closing prices per share of such Common Stock for the ten (10)
consecutive Trading Days immediately following such date; provided, however,
                                                          --------  ------- 
that in the event that the Current Market Price per share of the Common Stock is
determined during a period following the announcement by the issuer of such
Common Stock of (A) any dividend or distribution on such Common Stock payable in
shares of such Common Stock or securities convertible into shares of such Common
Stock (other than Rights), or (B) any subdivision, combination or
reclassification of such Common Stock, and prior to the expiration of the
requisite thirty (30) Trading Day or ten (10) Trading Day period, as set forth
above, after the ex-dividend date for such dividend or distribution, or the
record date for such subdivision, combination or reclassification, then, and in
each such case, the Current Market Price shall be properly adjusted to take into
account ex-dividend trading. The closing price for each day shall be the last
sale price, regular way, or, in case no such sale takes place on such day, the
average of the closing bid and asked prices, regular way, in either case as
reported in the principal consolidated transaction reporting system with respect
to securities listed on the principal national securities exchange on which the
shares of Common Stock are listed or admitted to trading or, if the shares of
Common Stock are not listed or admitted to trading on any national securities
exchange, the last quoted price or, if not so quoted, the average of the high
bid and low asked prices in the over-the-counter market, as reported by Nasdaq
or such other system then in use, or, if on any such date the shares of Common
Stock are not quoted by any such organization, the average of the closing bid
and asked prices as furnished by a professional market maker making a market in
the Common Stock selected by the Board. If on any such date no market maker is
making a market in the Common Stock, the fair value of such shares on such date
as determined in good faith by the Board shall be used. The term "Trading Day"
                                                                   ----------- 
shall mean a day on which the principal national securities exchange on which
the shares of Common Stock are listed or admitted to trading is open for the
transaction of business or, if the shares of Common Stock are not listed or
admitted to trading on any national securities exchange, a Business Day.  If the
Common Stock is not publicly held or not so listed or traded, Current Market
Price per share shall mean the fair value per share as determined in good faith
by the Board whose determination 
<PAGE>
 
shall be described in a statement filed with the Rights Agent and shall be
conclusive for all purposes.

                (ii) For the purpose of any computation hereunder, the Current
Market Price per share of Preferred Stock shall be determined in the same manner
as set forth above for the Common Stock in clause (i) of this Section 11(d)
(other than the last sentence thereof). If the Current Market Price per share of
Preferred Stock cannot be determined in the manner provided above or if the
Preferred Stock is not publicly held or listed or traded in a manner described
in clause (i) of this Section 11(d), the Current Market Price per share of
Preferred Stock shall be conclusively deemed to be an amount equal to 100 (as
such number may be appropriately adjusted for such events as stock splits, stock
dividends and recapitalizations with respect to the Common Stock occurring after
the date of this Agreement) multiplied by the Current Market Price per share of
the Common Stock. If neither the Common Stock nor the Preferred Stock is
publicly held or so listed or traded, Current Market Price per share of the
Preferred Stock shall mean the fair value per share as determined in good faith
by the Board, whose determination shall be described in a statement filed with
the Rights Agent and shall be conclusive for all purposes. For all purposes of
this Agreement, the Current Market Price of one one-hundredth of a share of
Preferred Stock shall be equal to the Current Market Price of one share of
Preferred Stock divided by 100.

                (iii) For the purpose of any computation hereunder, the value of
any securities or assets other than Common Stock or Preferred Stock shall be the
fair value as determined in good faith by the Board, or, if at the time of such
determination there is an Acquiring Person, by a majority of the Continuing
Directors then in office, or, if there are no Continuing Directors, by a
nationally recognized investment banking firm selected by the Board, which
determination shall be described in a statement filed with the Rights Agent and
shall be conclusive for all purposes.

          (e) Anything herein to the contrary notwithstanding, no adjustment in
the Purchase Price shall be required unless such adjustment would require an
increase or decrease of at least one percent (1%) in the Purchase Price;
provided, however, that any adjustments which by reason of this Section 11(e)
--------  -------                                                            
are not required to be made shall be carried forward and taken into account in
any subsequent adjustment. All calculations under this Section 11 shall be made
to the nearest cent or to the nearest ten-thousandth of a share of Common Stock
or other share or one-millionth of a share of Preferred Stock, as the case may
be. Notwithstanding the first sentence of this Section 11(e), any adjustment
required by this Section 11 shall be made no later than the earlier of (i) three
(3) years from the date of the transaction which mandates such adjustment, or
(ii) the Expiration Date.

          (f) If as a result of an adjustment made pursuant to Section 11(a)(ii)
or Section 13(a) hereof, the holder of any Right thereafter exercised shall
become entitled to receive any shares of capital stock other than Preferred
Stock, thereafter the number of such other shares so receivable upon exercise of
any Right and the Purchase Price thereof shall be subject to adjustment from
time to time in a manner and on terms as nearly equivalent as practicable to the
provisions with respect to the Preferred Stock contained in Sections 11(a), (b),
(c), (e), (g), (h), (i), (j), (k) and (m) hereof, and the provisions of Sections
7, 9, 10, 13 and 14 hereof with respect to the Preferred Stock shall apply on
like terms to any such other shares.

          (g) All Rights originally issued by the Company subsequent to any
adjustment made to the Purchase Price hereunder shall evidence the right to
purchase, at the adjusted Purchase Price, the number of one one-hundredths of a
share of Preferred Stock 
<PAGE>
 
purchasable from time to time hereunder upon exercise of the Rights, all subject
to further adjustment as provided herein.

          (h) Unless the Company shall have exercised its election as provided
in Section 11(i) hereof, upon each adjustment of the Purchase Price as a result
of the calculations made in Sections 11(b) and (c) hereof, each Right
outstanding immediately prior to the making of such adjustment shall thereafter
evidence the right to purchase, at the adjusted Purchase Price, that number of
one one-hundredths of a share of Preferred Stock obtained by (i) multiplying (x)
the number of one one-hundredths of a share covered by a Right immediately prior
to this adjustment, by (y) the Purchase Price in effect immediately prior to
such adjustment of the Purchase Price, and (ii) dividing the product so obtained
by the Purchase Price in effect immediately after such adjustment of the
Purchase Price.

          (i) The Company may elect on or after the date of any adjustment of
the Purchase Price to adjust the number of Rights, in lieu of any adjustment in
the number of shares of Preferred Stock purchasable upon the exercise of a
Right.  Each of the Rights outstanding after the adjustment in the number of
Rights shall be exercisable for the number of one one-hundredths of a share of
Preferred Stock for which a Right was exercisable immediately prior to such
adjustment.  Each Right held of record prior to such adjustment of the number of
Rights shall become that number of Rights (calculated to the nearest one-ten-
thousandth) obtained by dividing the Purchase Price in effect immediately prior
to adjustment of the Purchase Price by the Purchase Price in effect immediately
after adjustment of the Purchase Price.  The Company shall make a public
announcement of its election to adjust the number of Rights, indicating the
record date for the adjustment, and, if known at the time, the amount of the
adjustment to be made. This record date may be the date on which the Purchase
Price is adjusted or any day thereafter, but, if the Rights Certificates have
been issued, shall be at least ten (10) days later than the date of the public
announcement. If Rights Certificates have been issued, upon each adjustment of
the number of Rights pursuant to this Section 11(i), the Company shall, as
promptly as practicable, cause to be distributed to holders of record of Rights
Certificates on such record date Rights Certificates evidencing, subject to
Section 14 hereof, the additional Rights to which such holders shall be entitled
as a result of such adjustment, or, at the option of the Company, shall cause to
be distributed to such holders of record in substitution and replacement for the
Rights Certificates held by such holders prior to the date of adjustment, and
upon surrender thereof, if required by the Company, new Rights Certificates
evidencing all the Rights to which such holders shall be entitled after such
adjustment. Rights Certificates so to be distributed shall be issued, executed
and countersigned in the manner provided for herein (and may bear, at the option
of the Company, the adjusted Purchase Price) and shall be registered in the
names of the holders of record of Rights Certificates on the record date
specified in the public announcement.

          (j) Irrespective of any adjustment or change in the Purchase Price or
the number of one one-hundredths of a share of Preferred Stock issuable upon the
exercise of the Rights, the Rights Certificates theretofore and thereafter
issued may continue to express the Purchase Price per share and the number of
shares which were expressed in the initial Rights Certificates issued hereunder.

          (k) Before taking any action that would cause an adjustment reducing
the Purchase Price below the then par value of the shares of Common Stock
issuable upon exercise of the Rights, the Company shall take any corporate
action which may, in the opinion of its counsel, be necessary in order that the
Company may validly and legally issue fully paid and nonassessable such number
of one one-hundredths of a share of Preferred Stock at such adjusted Purchase
Price.
<PAGE>
 
          (l) In any case in which this Section 11 shall require that an
adjustment in the Purchase Price be made effective as of a record date for a
specified event, the Company may elect to defer until the occurrence of such
event the issuance to the holder of any Right exercised after such record date
the number of one one-hundredths of a share of Preferred Stock and other capital
stock or securities of the Company, if any, issuable upon such exercise over and
above the number of one one-hundredths of a share of Preferred Stock and other
capital stock or securities of the Company, if any, issuable upon such exercise
on the basis of the Purchase Price in effect prior to such adjustment; provided,
                                                                       -------- 
however, that the Company shall deliver to such holder a due bill or other
-------                                                                   
appropriate instrument evidencing such holder's right to receive such additional
shares or securities upon the occurrence of the event requiring such adjustment.

          (m) Anything in this Section 11 to the contrary notwithstanding, the
Company shall be entitled to make such reductions in the Purchase Price, in
addition to those adjustments expressly required by this Section 11, as and to
the extent that in their good faith judgment the Board shall determine to be
advisable in order that any (i) consolidation or subdivision of the Preferred
Stock, (ii) issuance wholly for cash of any shares of Preferred Stock at less
than the Current Market Price, (iii) issuance wholly for cash of shares of
Preferred Stock or securities which by their terms are convertible into or
exchangeable for shares of Preferred Stock, (iv) stock dividends, or (v)
issuance of rights, options or warrants referred to in this Section 11,
hereafter made by the Company to holders of its Preferred Stock shall not be
taxable to such stockholders.

          (n) The Company covenants and agrees that it shall not, at any time
after the Distribution Date, (i) consolidate with any other Person (other than a
Subsidiary of the Company in a transaction that complies with Section 11(o)
hereof), (ii) merge with or into any other Person (other than a Subsidiary of
the Company in a transaction which complies with Section 11(o) hereof), or (iii)
sell or transfer (or permit any Subsidiary to sell or transfer), in one
transaction, or a series of related transactions, assets or earning power
aggregating more than 50% of the assets or earning power of the Company and its
Subsidiaries (taken as a whole) to any other Person or Persons (other than the
Company or any of its Subsidiaries in one or more transactions each of which
complies with Section 11(o) hereof), if (x) at the time of or immediately after
such consolidation, merger or sale there are any rights, warrants or other
instruments or securities outstanding or agreements in effect that would
substantially diminish or otherwise eliminate the benefits intended to be
afforded by the Rights or (y) prior to, simultaneously with or immediately after
such consolidation, merger or sale, the stockholders of the Person who
constitutes, or would constitute, the "Principal Party" for purposes of Section
                                       ---------------                         
13(a) hereof shall have received a distribution of Rights previously owned by
such Person or any of its Affiliates and Associates.

          (o) The Company covenants and agrees that, after the Distribution
Date, it will not, except as permitted by Section 23 or Section 27 hereof, take
(or permit any Subsidiary to take) any action if at the time such action is
taken it is reasonably foreseeable that such action will diminish substantially
or otherwise eliminate the benefits intended to be afforded by the Rights.

          (p) Anything in this Agreement to the contrary notwithstanding, in the
event that the Company shall at any time after the Rights Dividend Declaration
Date and prior to the Distribution Date (i) declare a dividend on the
outstanding shares of Common Stock payable in shares of Common Stock, (ii)
subdivide the outstanding shares of Common Stock, or (iii) combine the
outstanding shares of Common Stock into a smaller number of shares, the number
of Rights associated with each share of Common Stock then outstanding, or issued
or delivered thereafter but prior to the Distribution Date, shall be
proportionately adjusted so that the number of Rights 
<PAGE>
 
thereafter associated with each share of Common Stock following any such event
shall equal the result obtained by multiplying the number of Rights associated
with each share of Common Stock immediately prior to such event by a fraction
the numerator of which shall be the total number of shares of Common Stock
outstanding immediately prior to the occurrence of the event and the denominator
of which shall be the total number of shares of Common Stock outstanding
immediately following the occurrence of such event.

          (q) The failure by the Continuing Directors to declare (or the
Independent Directors to concur therewith) a Person to be an Adverse Person
following such Person becoming the Beneficial Owner of 15% or more of the
outstanding Common Stock shall not imply that such Person is not an Adverse
Person or limit such directors' right at any time in the future to declare such
Person to be an Adverse Person.

        Section 12. Certificate of Adjusted Purchase Price or Number of Shares.
                    ----------------------------------------------------------
Whenever an adjustment is made as provided in Section 11 and Section 13
hereof, the Company shall (a) promptly prepare a certificate setting forth such
adjustment and a brief statement of the facts accounting for such adjustment,
(b) promptly file with the Rights Agent, and with each transfer agent for the
Preferred Stock and the Common Stock, a copy of such certificate, and (c) mail a
brief summary thereof to each holder of a Rights Certificate (or, if prior to
the Distribution Date, to each holder of a certificate representing shares of
Common Stock) in accordance with Section 26 hereof. The Rights Agent shall be
fully protected in relying on any such certificate and on any adjustment therein
contained.

        Section 13.  Consolidation, Merger or Sale or Transfer of Assets or 
                     ------------------------------------------------------
Earning Power.
-------------

          (a) In the event that, following the Stock Acquisition Date, directly
or indirectly, (x) the Company shall consolidate with, or merge with and into,
any other Person (other than a Subsidiary of the Company in a transaction that
complies with Section 11(o) hereof), and the Company shall not be the continuing
or surviving corporation of such consolidation or merger, (y) any Person (other
than a Subsidiary of the Company in a transaction that complies with Section
11(o) hereof) shall consolidate with, or merge with or into, the Company, and
the Company shall be the continuing or surviving corporation of such
consolidation or merger and, in connection with such consolidation or merger,
all or part of the outstanding shares of Common Stock shall be changed into or
exchanged for stock or other securities of any other Person or cash or any other
property, or (z) the Company shall sell or otherwise transfer (or one or more of
its Subsidiaries shall sell or otherwise transfer), in one transaction or a
series of related transactions, assets or earning power aggregating more than
50% of the assets or earning power of the Company and its Subsidiaries (taken as
a whole) to any Person or Persons (other than the Company or any Subsidiary of
the Company in one or more transactions each of which complies with Section
11(o) hereof), then, and in each such case and except as contemplated in Section
13(d) hereof, proper provision shall be made so that:  (i) each holder of a
Right, except as provided in Section 7(e) hereof, shall thereafter have the
right to receive, upon the exercise thereof at the then current Purchase Price
in accordance with the terms of this Agreement, such number of validly
authorized and issued, fully paid, nonassessable and freely tradeable shares of
Common Stock of the Principal Party (as such term is hereinafter defined), not
subject to any liens, encumbrances, rights of first refusal or other adverse
claims, as shall be equal to the result obtained by (1) multiplying the then
current Purchase Price by the number of one one-hundredths of a share of
Preferred Stock for which a Right was exercisable immediately prior to the first
occurrence of a Section 13 Event (or, if a Section 11(a)(ii) Event has occurred
prior to the first occurrence of a Section 13 Event, multiplying the number of
such one one-hundredths of a share for which a Right was exercisable 
<PAGE>
 
immediately prior to the first occurrence of a Section 11(a)(ii) Event by the
Purchase Price in effect immediately prior to such first occurrence), and
dividing that product (which, following the first occurrence of a Section 13
Event, shall be referred to as the "Purchase Price" for each Right and for all
                                    --------------
purposes of this Agreement) by (2) 50% of the Current Market Price (determined
pursuant to Section 11(d)(i) hereof) per share of the Common Stock of such
Principal Party on the date of consummation of such Section 13 Event; (ii) such
Principal Party shall thereafter be liable for, and shall assume, by virtue of
such Section 13 Event, all the obligations and duties of the Company pursuant to
this Agreement; (iii) the term "Company" shall thereafter be deemed to refer to
                                -------
such Principal Party, it being specifically intended that the provisions of
Section 11 hereof shall apply only to such Principal Party following the first
occurrence of a Section 13 Event; (iv) such Principal Party shall take such
steps (including, but not limited to, the reservation of a sufficient number of
shares of its Common Stock) in connection with the consummation of any such
transaction as may be necessary to assure that the provisions hereof shall
thereafter be applicable, as nearly as reasonably may be, in relation to its
shares of Common Stock thereafter deliverable upon the exercise of the Rights;
and (v) the provisions of Section 11(a)(ii) hereof shall be of no effect
following the first occurrence of any Section 13 Event.

                (b)  "Principal Party" shall mean
                      --------------- 
                     (i)   in the case of any transaction described in clause
                (x) or (y) of the first sentence of Section 13(a) hereof, the
                Person that is the issuer of any securities into which shares of
                Common Stock of the Company are converted in such merger or
                consolidation, and if no securities are so issued, the Person
                that is the other party to such merger or consolidation; and

                     (ii)  in the case of any transaction described in
                clause (z) of the first sentence of Section 13(a) hereof, the
                Person that is the party receiving the greatest portion of the
                assets or earning power transferred pursuant to such transaction
                or transactions;

provided, however, that in any such case, (1) if the Common Stock of such Person
--------  -------                                                               
is not at such time and has not been continuously over the preceding twelve (12)
month period registered under Section 12 of the Exchange Act, and such Person is
a direct or indirect Subsidiary of another Person the Common Stock of which is
and has been so registered, "Principal Party" shall refer to such other Person;
and (2) in case such Person is a Subsidiary, directly or indirectly, of more
than one Person, the Common Stocks of two or more of which are and have been so
registered, "Principal Party" shall refer to whichever of such Persons is the
issuer of the Common Stock having the greatest aggregate market value.

                (c) The Company shall not consummate any such consolidation,
merger, sale or transfer unless the Principal Party shall have a sufficient
number of authorized shares of its Common Stock which have not been issued or
reserved for issuance to permit the exercise in full of the Rights in accordance
with this Section 13 and unless prior thereto the Company and such Principal
Party shall have executed and delivered to the Rights Agent a supplemental
agreement providing for the terms set forth in paragraphs (a) and (b) of this
Section 13 and further providing that, as soon as practicable after the date of
any Section 13 Event, the Principal Party will:

                    (i) prepare and file a registration statement under the Act,
with respect to the Rights and the securities purchasable upon exercise of the
Rights on an appropriate 
<PAGE>
 
form, and will use its best efforts to cause such registration statement to (A)
become effective as soon as practicable after such filing and (B) remain
effective (with a prospectus at all times meeting the requirements of the Act)
until the Expiration Date; and

                    (ii) deliver to holders of the Rights historical financial
statements for the Principal Party and each of its Affiliates that comply in all
respects with the requirements for registration on Form 10 under the Exchange
Act.

The provisions of this Section 13 shall similarly apply to successive mergers or
consolidations or sales or other transfers.  In the event that a Section 13
Event shall occur at any time after the occurrence of a Section 11(a)(ii) Event,
the Rights which have not theretofore been exercised shall thereafter become
exercisable in the manner described in Section 13(a) hereof.

          (d) Notwithstanding anything in this Agreement to the contrary,
Section 13 shall not be applicable to a transaction described in subparagraphs
(x) and (y) of Section 13(a) if (i) such transaction is consummated with a
Person or Persons who acquired shares of Common Stock pursuant to a tender offer
or exchange offer for all outstanding shares of Common Stock which complies with
the provisions of Section 11(a)(ii)(B) hereof (or a wholly owned subsidiary of
any such Person or Persons), (ii) the price per share of Common Stock offered in
such transaction is not less than the price per share of Common Stock paid to
all holders of shares of Common Stock whose shares were purchased pursuant to
such tender offer or exchange offer, and (iii) the form of consideration being
offered to the remaining holders of shares of Common Stock pursuant to such
transaction is the same as the form of consideration paid pursuant to such
tender offer or exchange offer.  Upon consummation of any such transaction
contemplated by this Section 13(d), all Rights hereunder shall expire.

        Section 14.  Fractional Rights and Fractional Shares
                     ---------------------------------------
                (a) The Company shall not be required to issue fractions of
Rights, except prior to the Distribution Date as provided in Section 11(p)
hereof, or to distribute Rights Certificates that evidence fractional Rights. If
the Company determines not to issue fractional Rights, there shall be paid in
lieu thereof to the registered holders of the Rights Certificates with regard to
which such fractional Rights would otherwise be issuable, an amount in cash
equal to the same fraction of the current market value of a whole Right. For
purposes of this Section 14(a), the current market value of a whole Right shall
be the closing price of the Rights for the Trading Day immediately prior to the
date on which such fractional Rights would have been otherwise issuable. The
closing price of the Rights for any day shall be the last sale price, regular
way, or, in case no such sale takes place on such day, the average of the
closing bid and asked prices, regular way, in either case as reported in the
principal consolidated transaction reporting system with respect to securities
listed on the principal national securities exchange on which the Rights are
listed or admitted to trading, or if the Rights are not listed or admitted to
trading on any national securities exchange, the last quoted price or, if not so
quoted, the average of the high bid and low asked prices in the over-the-counter
market, as reported by Nasdaq or such other system then in use or, if on any
such date the Rights are not quoted by any such organization, the average of the
closing bid and asked prices as furnished by a professional market maker making
a market in the Rights selected by the Board. If on any such date no such market
maker is making a market in the Rights the fair value of the Rights on such date
as determined in good faith by the Board shall be used.

                (b) The Company shall not be required to issue fractions of 
shares of
<PAGE>
 
Preferred Stock (other than fractions which are integral multiples of one one-
hundredth of a share of Preferred Stock) upon exercise of the Rights or to
distribute certificates that evidence fractional shares of Preferred Stock
(other than fractions which are integral multiples of one one-hundredth of a
share of Preferred Stock).  In lieu of fractional shares of Preferred Stock that
are not integral multiples of one one-hundredth of a share of Preferred Stock,
the Company may pay to the registered holders of Rights Certificates, with
regard to which such fractional shares of Preferred Stock would otherwise be
issuable, at the time such Rights are exercised as herein provided, an amount in
cash equal to the same fraction of the current market value of one one-hundredth
of a share of Preferred Stock.  For purposes of this Section 14(b), the current
market value of one one-hundredth share of Preferred Stock shall be one one-
hundredth of the closing price per share of Common Stock (determined pursuant to
Section 11(d)(ii) hereof) on the Trading Day immediately prior to the date of
such exercise.

                (c) Following the occurrence of a Triggering Event, the Company
shall not be required to issue fractions of shares of Common Stock upon exercise
of the Rights or to distribute certificates which evidence fractional shares of
Common Stock. In lieu of fractional shares of Common Stock, the Company may pay
to the registered holders of Rights Certificates at the time such Rights are
exercised as herein provided an amount in cash equal to the same fraction of the
current market value of one share of Common Stock. For purposes of this Section
14(c), the current market value of one share of Common Stock shall be the
closing price of one share of Common Stock (as determined pursuant to Section
11(d)(i) hereof) for the Trading Day immediately prior to the date of such
exercise.

                (d) The holder of a Right by the acceptance of the Right
expressly waives his right to receive any fractional Rights or any fractional
shares upon exercise of a Right, except as permitted by this Section 14.


        Section 15. Rights of Action. All rights of action in respect of this
                    ----------------
Agreement, other than rights of action vested in the Rights Agent in Section 18
hereof, are vested in the respective registered holders of the Rights
Certificates (and, prior to the Distribution Date, the registered holders of the
Common Stock); and any registered holder of any Rights Certificate (or, prior to
the Distribution Date, of the Common Stock), without the consent of the Rights
Agent or of the holder of any other Rights Certificate (or, prior to the
Distribution Date, of the Common Stock), may, in his own behalf and for his own
benefit, enforce, and may institute and maintain any suit, action or proceeding
against the Company to enforce, or otherwise act in respect of, his right to
exercise the Rights evidenced by such Rights Certificate in the manner provided
in such Rights Certificate and in this Agreement. Without limiting the foregoing
or any remedies available to the holders of Rights, it is specifically
acknowledged that the holders of Rights would not have an adequate remedy at law
for any breach of this Agreement and shall be entitled to specific performance
of the obligations hereunder and injunctive relief against actual or threatened
violations of the obligations hereunder of any Person subject to this Agreement.

        Section 16. Agreement of Rights Holders. Every holder of a Right, by
                    ---------------------------
accepting the same, consents and agrees with the Company and the Rights Agent
and with every other holder of a Right that:

                (a) prior to the Distribution Date, the Rights will be
transferable only in connection with the transfer of Common Stock;

                (b) after the Distribution Date, the Rights Certificates are
transferable only 
<PAGE>
 
on the registry books of the Rights Agent if surrendered at the principal office
or offices of the Rights Agent designated for such purposes, duly endorsed or
accompanied by a proper instrument of transfer and with the appropriate forms of
assignment and certificates duly completed and fully executed;

                (c) subject to Section 6(a) and Section 7(f) hereof, the Company
and the Rights Agent may deem and treat the person in whose name a Rights
Certificate (or, prior to the Distribution Date, the associated Common Stock
certificate) is registered as the absolute owner thereof and of the Rights
evidenced thereby (notwithstanding any notations of ownership or writing on the
Rights Certificates or the associated Common Stock certificate made by anyone
other than the Company or the Rights Agent) for all purposes whatsoever, and
neither the Company nor the Rights Agent, subject to the last sentence of
Section 7(e) hereof, shall be required to be affected by any notice to the
contrary; and

                (d) notwithstanding anything in this Agreement to the contrary,
neither the Company nor the Rights Agent shall have any liability to any holder
of a Right or other Person as a result of its inability to perform any of its
obligations under this Agreement by reason of any preliminary or permanent
injunction or other order, decree or ruling issued by a court of competent
jurisdiction or by a governmental, regulatory or administrative agency or
commission, or any statute, rule, regulation or executive order promulgated or
enacted by any governmental authority, prohibiting or otherwise restraining
performance of such obligation; provided, however, the Company must use its best
                                --------  -------                               
efforts to have any such order, decree or ruling lifted or otherwise overturned
as soon as possible.

        Section 17.  Rights Certificate Holder Not Deemed a Stockholder.
                     --------------------------------------------------
No holder, as such, of any Rights Certificate shall be entitled to vote, receive
dividends or be deemed for any purpose the holder of the number of one one-
hundredths of a share of Preferred Stock or any other securities of the Company
which may at any time be issuable on the exercise of the Rights represented
thereby, nor shall anything contained herein or in any Rights Certificate be
construed to confer upon the holder of any Rights Certificate, as such, any of
the rights of a stockholder of the Company or any right to vote for the election
of directors or upon any matter submitted to stockholders at any meeting
thereof, or to give or withhold consent to any corporate action, or to receive
notice of meetings or other actions affecting stockholders (except as provided
in Section 25 hereof), or to receive dividends or subscription rights, or
otherwise, until the Right or Rights evidenced by such Rights Certificate shall
have been exercised in accordance with the provisions hereof.

        Section 18.  Concerning the Rights Agent.
                     ---------------------------

                (a) The Company agrees to pay to the Rights Agent reasonable
compensation for all services rendered by it hereunder and, from time to time,
on demand of the Rights Agent, its reasonable expenses and counsel fees and
disbursements and other disbursements incurred in the administration and
execution of this Agreement and the exercise and performance of its duties
hereunder.  The Company also agrees to indemnify the Rights Agent for, and to
hold it harmless against, any loss, liability or expense, incurred without
negligence, bad faith or willful misconduct on the part of the Rights Agent, for
anything done or omitted by the Rights Agent in connection with the acceptance
and administration of this Agreement, including the costs and expenses of
defending against any claim of liability in the premises.
<PAGE>
 
                (b) The Rights Agent shall be protected and shall incur no
liability for or in respect of any action taken, suffered or omitted by it in
connection with its administration of this Agreement in reliance upon any Rights
Certificate or certificate for Common Stock or for other securities of the
Company, instrument of assignment or transfer, power of attorney, endorsement,
affidavit, letter, notice, direction, consent, certificate, statement, or other
paper or document believed by it to be genuine and to be signed, executed and,
where necessary, verified or acknowledged, by the proper Person or Persons.

        Section 19.  Merger or Consolidation or Change of Name of Rights Agent.
                     ---------------------------------------------------------
                (a) Any corporation into which the Rights Agent or any successor
Rights Agent may be merged or with which it may be consolidated, or any
corporation resulting from any merger or consolidation to which the Rights Agent
or any successor Rights Agent shall be a party, or any corporation succeeding to
the corporate trust or stock transfer business of the Rights Agent or any
successor Rights Agent, shall be the successor to the Rights Agent under this
Agreement without the execution or filing of any paper or any further act on the
part of any of the parties hereto; provided, however, that such corporation
                                   --------  -------                       
would be eligible for appointment as a successor Rights Agent under the
provisions of Section 21 hereof.  In case at the time such successor Rights
Agent shall succeed to the agency created by this Agreement, any of the Rights
Certificates shall have been countersigned but not delivered, any such successor
Rights Agent may adopt the counter-signature of a predecessor Rights Agent and
deliver such Rights Certificates so countersigned; and in case at that time any
of the Rights Certificates shall not have been countersigned, any successor
Rights Agent may countersign such Rights Certificates either in the name of the
predecessor or the name of the successor Rights Agent; and in all such cases
such Rights Certificates shall have the full force provided in the Rights
Certificates and in this Agreement.

          (b) In case at any time the name of the Rights Agent shall be changed
and at such time any of the Rights Certificates shall have been countersigned
but not delivered, the Rights Agent may adopt the countersignature under its
prior name and deliver Rights Certificates so countersigned; and in case at that
time any of the Rights Certificates shall not have been countersigned, the
Rights Agent may countersign such Rights Certificates either in its prior name
or in its changed name; and in all such cases such Rights Certificates shall
have the full force provided in the Rights Certificates and in this Agreement.


        Section 20.  Duties of Rights Agent.  The Rights Agent undertakes the
                     ----------------------
duties and obligations imposed by this Agreement upon the following terms and
conditions, by all of which the Company and the holders of Rights Certificates,
by their acceptance thereof, shall be bound:

                (a) The Rights Agent may consult with legal counsel (who may be
legal counsel for the Company), and the opinion of such counsel shall be full
and complete authorization and protection to the Rights Agent as to any action
taken or omitted by it in good faith and in accordance with such opinion.

                (b) Whenever in the performance of its duties under this
Agreement the Rights Agent shall deem it necessary or desirable that any fact or
matter (including, without limitation, the identity of any Acquiring Person or
Adverse Person and the determination of Current Market Price) be proved or
established by the Company prior to taking or suffering any action hereunder,
such fact or matter (unless other evidence in respect thereof be herein
specifically prescribed) may be deemed to be conclusively proved and established
by a certificate
<PAGE>
 
signed by the President, any Vice President, the Treasurer, any Assistant
Treasurer, the Secretary or any Assistant Secretary of the Company and delivered
to the Rights Agent; and such certificate shall be full authorization to the
Rights Agent for any action taken or suffered in good faith by it under the
provisions of this Agreement in reliance upon such certificate.

                (c) The Rights Agent shall be liable hereunder only for its own
negligence, bad faith or willful misconduct.

                (d) The Rights Agent shall not be liable for or by reason of any
of the statements of fact or recitals contained in this Agreement or in the
Rights Certificates or be required to verify the same (except as to its
countersignature on such Rights Certificates), but all such statements and
recitals are and shall be deemed to have been made by the Company only.

                (e) The Rights Agent shall not be under any responsibility in
respect of the validity of this Agreement or the execution and delivery hereof
(except the due execution hereof by the Rights Agent) or in respect of the
validity or execution of any Rights Certificate (except its countersignature
thereof); nor shall it be responsible for any breach by the Company of any
covenant or condition contained in this Agreement or in any Rights Certificate;
nor shall it be responsible for any adjustment required under the provisions of
Section 11 or Section 13 hereof or responsible for the manner, method or amount
of any such adjustment or the ascertaining of the existence of facts that would
require any such adjustment (except with respect to the exercise of Rights
evidenced by Rights Certificates after receipt of a certificate describing any
such adjustment furnished in accordance with Section 12); nor shall it by any
act hereunder be deemed to make any representation or warranty as to the
authorization or reservation of any shares of Common Stock to be issued pursuant
to this Agreement or any Rights Certificate or as to whether any shares of
Common Stock will, when so issued, be validly authorized and issued, fully paid
and nonassessable.

                (f) The Company agrees that it will perform, execute,
acknowledge and deliver or cause to be performed, executed, acknowledged and
delivered all such further and other acts, instruments and assurances as may
reasonably be required by the Rights Agent for the carrying out or performing by
the Rights Agent of the provisions of this Agreement.

                (g) The Rights Agent is hereby authorized and directed to accept
instructions with respect to the performance of its duties hereunder from the
President, any Vice President, the Secretary, any Assistant Secretary, the
Treasurer or any Assistant Treasurer of the Company, and to apply to such
officers for advice or instructions in connection with its duties, and it shall
not be liable for any action taken or suffered to be taken by it in good faith
in accordance with instructions of any such officer.

                (h) The Rights Agent and any stockholder, director, officer or
employee of the Rights Agent may buy, sell or deal in any of the Rights or other
securities of the Company or become pecuniarily interested in any transaction in
which the Company may be interested, or contract with or lend money to the
Company or otherwise act as fully and freely as though it were not Rights Agent
under this Agreement. Nothing herein shall preclude the Rights Agent from acting
in any other capacity for the Company or for any other legal entity.

                (i) The Rights Agent may execute and exercise any of the rights
or powers hereby vested in it or perform any duty hereunder either itself or by
or through its attorneys or agents, and the Rights Agent shall not be answerable
or accountable for any act, default, neglect 
<PAGE>
 
or misconduct of any such attorneys or agents or for any loss to the Company
resulting from any such act, default, neglect or misconduct; provided, however,
                                                             --------  -------
reasonable care was exercised in the selection and continued employment thereof.

                (j) No provision of this Agreement shall require the Rights
Agent to expend or risk its own funds or otherwise incur any financial liability
in the performance of any of its duties hereunder or in the exercise of its
rights if there shall be reasonable grounds for believing that repayment of such
funds or adequate indemnification against such risk or liability is not
reasonably assured to it.

                (k) If, with respect to any Rights Certificate surrendered to
the Rights Agent for exercise or transfer, the certificate contained in the form
of assignment or the form of election to purchase set forth on the reverse
thereof, as the case may be, has either not been completed or indicates an
affirmative response to clause 1 or 2 thereof, the Rights Agent shall not take
any further action with respect to such requested exercise of transfer without
first consulting with the Company.

        Section 21.  Change of Rights Agent.  The Rights Agent or any successor
                     ----------------------
 Rights Agent may resign and be discharged from its duties under this Agreement
upon thirty (30) days' notice in writing mailed to the Company, and to each
transfer agent of the Common Stock and Preferred Stock, by registered or
certified mail, and to the holders of the Rights Certificates by first-class
mail. The Company may remove the Rights Agent or any successor Rights Agent upon
thirty (30) days' notice in writing, mailed to the Rights Agent or successor
Rights Agent, as the case may be, and to each transfer agent of the Common Stock
and Preferred Stock, by registered or certified mail, and to the holders of the
Rights Certificates by first-class mail. If the Rights Agent shall resign or be
removed or shall otherwise become incapable of acting, the Company shall appoint
a successor to the Rights Agent. If the Company shall fail to make such
appointment within a period of thirty (30) days after giving notice of such
removal or after it has been notified in writing of such resignation or
incapacity by the resigning or incapacitated Rights Agent or by any registered
holder of a Rights Certificate (who shall, with such notice, submit his Rights
Certificate for inspection by the Company), then any registered holder of any
Rights Certificate may apply to any court of competent jurisdiction for the
appointment of a new Rights Agent. Any successor Rights Agent, whether appointed
by the Company or by such a court, shall be (a) a corporation organized and
doing business under the laws of the United States or any state thereof in good
standing, which is authorized under such laws to exercise corporate trust or
stock transfer powers and is subject to supervision or examination by federal or
state authority and which has at the time of its appointment as Rights Agent a
combined capital and surplus of at least $50,000,000 or (b) an affiliate of a
corporation described in clause (a) of this sentence. After appointment, the
successor Rights Agent shall be vested with the same powers, rights, duties and
responsibilities as if it had been originally named as Rights Agent without
further act or deed; but the predecessor Rights Agent shall deliver and transfer
to the successor Rights Agent any property at the time held by it hereunder, and
execute and deliver any further assurance, conveyance, act or deed necessary for
the purpose. Not later than the effective date of any such appointment, the
Company shall file notice thereof in writing with the predecessor Rights Agent
and each transfer agent of the Common Stock and Preferred Stock, and mail a
notice thereof in writing to the registered holders of the Rights Certificates.
Failure to give any notice provided for in this Section 21, however, or any
defect therein, shall not affect the legality or validity of the resignation or
removal of the Rights Agent or the appointment of the successor Rights Agent, as
the case may be.
<PAGE>
 
        Section 22. Issuance of New Rights Certificates. Notwithstanding any 
                    -----------------------------------
of the provisions of this Agreement or of the Rights to the contrary, the
Company may, at its option, issue new Rights Certificates evidencing Rights in
such form as may be approved by the Board to reflect any adjustment or change in
the Purchase Price and the number or kind or class of shares or other securities
or property purchasable under the Rights Certificates made in accordance with
the provisions of this Agreement. In addition, in connection with the issuance
or sale of shares of Common Stock following the Distribution Date (other than
upon exercise of a Right) and prior to the redemption or expiration of the
Rights, the Company (a) shall, with respect to shares of Common Stock so issued
or sold pursuant to the exercise of stock options or under any employee plan or
arrangement, or upon the exercise, conversion or exchange of securities, notes,
warrants or debentures issued by the Company, and (b) may, in any other case, if
deemed necessary or appropriate by the Board, issue Rights Certificates
representing the appropriate number of Rights in connection with such issuance
or sale; provided, however, that (i) no such Rights Certificate shall be
         --------  -------             
issued if, and to the extent that, the Company shall be advised by counsel that
such issuance would create a significant risk of material adverse tax
consequences to the Company or the Person to whom such Rights Certificate would
be issued, and (ii) no such Rights Certificate shall be issued if, and to the
extent that, appropriate adjustment shall otherwise have been made in lieu of
the issuance thereof.

        Section 23. Redemption and Termination.
                    --------------------------

                (a) The Board may, at its option, at any time prior to the
earlier of (i) the Close of Business on the tenth day following the Stock
Acquisition Date (or, if the Stock Acquisition Date shall have occurred prior to
the Record Date, the close of business on the tenth day following the Record
Date), or (ii) the Final Expiration Date, redeem all but not less than all of
the then outstanding Rights at a redemption price of $.01 per Right, as such
amount may be appropriately adjusted to reflect any stock split, stock dividend
or similar transaction occurring after the date hereof (such redemption price
being hereinafter referred to as the "Redemption Price"); provided, however,
                                      ----------------    --------  -------  
that the Board may not redeem any Rights following an Adverse Person Event and
provided, further, that if the Board authorizes redemption of the Rights in
--------  -------
either of the circumstances set forth in clauses (i) and (ii) below, then there
must be Continuing Directors then in office and such authorization shall require
the concurrence of a majority of such Continuing Directors: (i) such
authorization occurs on or after the time a Person becomes an Acquiring Person,
or (ii) such authorization occurs on or after the date of a change (resulting
from a proxy or consent solicitation effected in compliance with applicable law
and the requirements of any national securities exchange or trading market on
which the Common Stock is listed) in a majority of the directors in office at
the commencement of such solicitation if any Person who is a participant in such
solicitation has stated (or, if upon the commencement of such solicitation, a
majority of the Board has determined in good faith) that such Person (or any of
its Affiliates or Associates) intends to take, or may consider taking, any
action which would result in such Person becoming an Acquiring Person or which
would cause the occurrence of a Triggering Event unless, concurrent with such
solicitation, such Person (or one or more of its Affiliates or Associates) is
making a cash tender offer pursuant to a Schedule 14D-1 (or any successor form)
filed with the Securities and Exchange Commission for all outstanding shares of
Common Stock not beneficially owned by such Person (or by its Affiliates or
Associates). If, following the occurrence of a Stock Acquisition Date and
following the expiration of the right of redemption set forth in the preceding
sentence but prior to any Triggering Event, (i) a Person who was an Acquiring
Person shall have transferred or otherwise disposed of a number of shares of
Common Stock in one or more transactions, not directly or indirectly involving
the Company or any of its Subsidiaries, which did not result in the occurrence
of a Triggering Event such that
<PAGE>
 
such Person is thereafter a Beneficial Owner of 15% or less of the outstanding
shares of Common Stock, and (ii) there are no other Persons, immediately
following the occurrence of the event described in clause (i), who are Acquiring
Persons, and (iii) the Board (with the concurrence of a majority of the
Continuing Directors) shall so approve, then the Company's right of redemption
set forth in the preceding sentence shall be reinstated and thereafter be
subject to the provisions of this Section 23. If following the occurrence of a
Stock Acquisition Date and following the expiration of the right of redemption
set forth in the first sentence hereof, but prior to any Triggering Event, the
Board may, at its option, redeem all but not less than all of the then
outstanding Rights at the Redemption Price, provided that (i) such redemption is
effected in connection with the approval by the Board of Directors of the
Company of, and the execution and delivery by the Company of an agreement
providing for, a merger, consolidation, sale or transfer of all or substantially
all of the assets of the Company or other business combination, in each case
which involves the Company but does not involve an Acquiring Person or an
Affiliate or Associate of an Acquiring Person or any other Person acting
directly or indirectly on behalf of or in association with any such Acquiring
Person, Affiliate or Associate and (ii) such redemption is approved by a
majority of the Continuing Directors. Notwithstanding anything contained in this
Agreement to the contrary, the Rights shall not be exercisable after the first
occurrence of a Section 11(a)(ii) Event until such time as the Company's right
of redemption set forth in the first sentence of this Section 23(a) has expired.

                (b) The Company may, at its option, pay the Redemption Price in
cash, shares of Common Stock (based on the Current Market Price as defined in
Section 11(d) hereof, of the Common Stock at the time of redemption) or any
other form of consideration deemed appropriate by the Board.

                (c) Immediately upon the action of the Board ordering the
redemption of the Rights, evidence of which shall have been filed with the
Rights Agent and without any further action and without any notice, the right to
exercise the Rights will terminate and the only right thereafter of the holders
of Rights shall be to receive the Redemption Price for each Right so held.
Promptly after the action of the Board ordering the redemption of the Rights,
the Company shall give notice of such redemption to the Rights Agent and the
holders of the then outstanding Rights by mailing such notice to all such
holders at each holder's last address as it appears upon the registry books of
the Rights Agent or, prior to the Distribution Date, on the registry books of
the Transfer Agent for the Common Stock. Any notice which is mailed in the
manner herein provided shall be deemed given, whether or not the holder receives
the notice. Each such notice of the redemption will state the method by which
the payment of the Redemption Price will be made.

        Section 24.  Exchange.  (a) At any time after any Person becomes an
                     --------
Acquiring Person or an Adverse Person, a majority of the Continuing Directors
may, at their option, exchange all or part of the then outstanding and
exercisable Rights (which (i) shall not include Rights that have become void
pursuant to Section 7(e) and (ii) shall include, without limitation, any Rights
issued after the Distribution Date in connection with the exercise of options
pursuant to any employee benefit plan of the Company or any Subsidiary of the
Company) for shares of Common Stock at an exchange ratio of one share of Common
Stock per Right, appropriately adjusted to reflect any stock split, stock
dividend or similar transaction occurring after the date hereof (such exchange
ratio being hereinafter referred to as the "Exchange Ratio"). Notwithstanding 
                                            --------------    
the foregoing, the Board of Directors shall not be empowered to effect such
exchange at any time after any Person (other than the Company, any of its
Subsidiaries, any employee benefit plan of the Company or any of its
Subsidiaries or any Person organized, appointed or established by the 
<PAGE>
 
Company or any of its Subsidiaries for or pursuant to the terms of any such
plan), together with all Affiliates and Associates of such Person, becomes the
Beneficial Owner of 50% or more of the shares of Common Stock then outstanding.

                (b) Immediately upon the action of the Continuing Directors
electing to exchange any Rights pursuant to Section 24(a) and without any
further action and without any notice, the right to exercise such Rights will
terminate and thereafter the only right of a holder of such Rights shall be to
receive that number of shares of Common Stock equal to the number of such Rights
held by such holder multiplied by the Exchange Ratio. The Company shall promptly
thereafter give notice of such exchange to the Rights Agent and the holders of
the Rights to be exchanged in the manner set forth in Section 26; provided,
                                                                  --------
however, that the failure to give, or any defect in, such notice shall not
--------  
affect the validity of such exchange. Any notice which is mailed in the manner
herein provided shall be deemed given, whether or not the holder receives the
notice. Each such notice of exchange will state the method by which the exchange
of the shares of Common Stock for Rights will be effected and, in the event of
any partial exchange, the number of Rights which will be exchanged. Any partial
exchange shall be effected pro rata based on the number of Rights (other than
Rights which have become void pursuant to Section 7(e)) held by each holder of
Rights.

                (c) In any exchange pursuant to this Section 24, the Company, at
its option, may substitute Common Stock Equivalents (as defined in Section
11(a)(iii)) for shares of Common Stock exchangeable for Rights, at the initial
rate of one Common Stock Equivalent for each share of Common Stock, as
appropriately adjusted to reflect adjustments in dividend, liquidation and
voting rights of Common Stock Equivalents pursuant to the terms thereof, so that
each Common Stock Equivalent delivered in lieu of each share of Common Stock
shall have essentially the same dividend, liquidation and voting rights as one
share of Common Stock.

                (d) In the event that the number of shares of Common Stock which
are authorized by the Company's certificate of incorporation but not outstanding
or reserved for issuance are not sufficient to permit an exchange of Rights as
contemplated by this Section 24, the Company shall take all such action as may
be necessary to authorize additional shares of Common Stock for issuance upon
exchange of the Rights.

                (e) The Company shall not be required to issue fractions of
shares of Common Stock or to distribute certificates that evidence fractional
shares of Common Stock. In lieu of fractional shares of Common Stock, the
Company may pay to the registered holders of Rights Certificates with regard to
which such fractional shares of Common Stock would otherwise be issuable, an
amount in cash equal to the same fraction of the current market value of a whole
share of Common Stock. For purposes of this Section 24(e), the current market
value of a whole share of Common Stock shall be the closing price per share of
Common Stock (determined pursuant to Section 11(d)(ii) hereof) on the Trading
Day immediately prior to the date of exchange pursuant to this Section 24.

        Section 25.  Notice of Certain Events.
                     ------------------------
                (a) In case the Company shall propose, at any time after the
Distribution Date, (i) to pay any dividend payable in stock of any class to the
holders of Preferred Stock or to make any other distribution to the holders of
Preferred Stock (other than a regular quarterly cash dividend out of earnings or
retained earnings of the Company), or (ii) to offer to the holders of Preferred
Stock rights or warrants to subscribe for or to purchase any additional shares
of 
<PAGE>
 
Preferred Stock or shares of stock of any class or any other securities, rights
or options, or (iii) to effect any reclassification of its Preferred Stock
(other than a reclassification involving only the subdivision of outstanding
shares of Preferred Stock), or (iv) to effect any consolidation or merger into
or with any other Person (other than a Subsidiary of the Company in a
transaction which complies with Section 11(o) hereof), or to effect any sale or
other transfer (or to permit one or more of its Subsidiaries to effect any sale
or other transfer), in one transaction or a series of related transactions, of
more than 50% of the assets or earning power of the Company and its Subsidiaries
(taken as a whole) to any other Person or Persons (other than the Company or any
of its Subsidiaries in one or more transactions each of which complies with
Section 11(o) hereof), or (v) to effect the liquidation, dissolution or winding
up of the Company, then, in each such case, the Company shall give to each
holder of a Rights Certificate, to the extent feasible, in accordance with
Section 26 hereof, a notice of such proposed action, which shall specify the
record date for the purposes of such stock dividend or distribution of rights or
warrants, or the date on which such reclassification, consolidation, merger,
sale, transfer, liquidation, dissolution, or winding up is to take place and the
date of participation therein by the holders of the shares of Preferred Stock,
if any such date is to be fixed, and such notice shall be so given in the case
of any action covered by clause (i) or (ii) above at least twenty (20) days
prior to the record date for determining holders of the shares of Preferred
Stock for purposes of such action, and in the case of any such other action, at
least twenty (20) days prior to the date of the taking of such proposed action
or the date of participation therein by the holders of the shares of Preferred
Stock, whichever shall be the earlier.

                (b) In case any Section 11(a)(ii) Event shall occur, then, in
any such case, (i) the Company shall as soon as practicable thereafter give to
each holder of a Rights Certificate, to the extent feasible, and in accordance
with Section 26 hereof, a notice of the occurrence of such event, which shall
specify the event and the consequences of the event to holders of Rights under
Section 11(a)(ii) hereof and (ii) all references in the preceding paragraph to
Common Stock shall, to the extent appropriate, also be deemed thereafter to
refer to other securities.

        Section 26.  Notices.  Notices or demands authorized by this Agreement
                     -------
to be given or made by the Rights Agent or by the holder of any Rights
Certificate to or on the Company shall be sufficiently given or made if sent by
first-class mail, postage prepaid, addressed (until another address is filed in
writing with the Rights Agent) as follows:

                
                PerSeptive Biosystems, Inc.
                500 Old Connecticut Path
                Framingham, MA 01701
                Attention:  President


Subject to the provisions of Section 21, any notice or demand authorized by this
Agreement to be given or made by the Company or by the holder of any Rights
Certificate to or on the Rights Agent shall be sufficiently given or made if
sent by first-class mail, postage prepaid, addressed (until another address is
filed in writing with the Company) as follows:


                American Stock Transfer & Trust Company
                40 Wall Street
                New York, New York  10005
                Attention:


Notices or demands authorized by this Agreement to be given or made by the
Company or the 
<PAGE>
 
Rights Agent to the holder of any Rights Certificate (or, if prior to the
Distribution Date, to the holder of certificates representing shares of Common
Stock) shall be sufficiently given or made if sent by first-class mail, postage
prepaid, addressed to such holder at the address of such holder as shown on the
registry books of the Company.

        Section 27.  Supplements and Amendments.  At any time prior to the Final
                     --------------------------
Amendment Date, and subject to the penultimate sentence of this Section 27, the
Company and the Rights Agent shall, if the Company so directs, supplement or
amend any provision of this Agreement without the approval of any holders of
certificates representing shares of Common Stock. From and after the Final
Amendment Date and subject to the penultimate sentence of this Section 27, the
Company and the Rights Agent shall, if the Company so directs, supplement or
amend this Agreement without the approval of any holders of Rights Certificates
in order (i) to cure any ambiguity, (ii) to correct or supplement any provision
contained herein which may be defective or inconsistent with any other
provisions herein, (iii) to shorten or lengthen any time period hereunder or
(iv) to change or supplement the provisions hereunder in any manner which the
Company may deem necessary or desirable and which shall not adversely affect the
interests of the holders of Rights Certificates (other than an Acquiring Person,
an Adverse Person or an Affiliate or Associate of such Person); provided,
                                                                --------
however, that this Agreement may not be supplemented or amended,  (A) whether
-------
before or after the Final Amendment Date, to lengthen a time period relating to
when the Rights may be redeemed or to modify the ability (or inability) of the
Continuing Directors to redeem the Rights, in either case at such time as the
Rights are not then redeemable or (B) after the Final Amendment Date, to
lengthen, pursuant to clause (iii) of this sentence, any other time period
unless such lengthening is for the purpose of protecting, enhancing or
clarifying the rights of or the benefits to the holders of Rights (other than
any Acquiring Person, an Adverse Person or an Associate or Affiliate of such
Person). Upon the delivery of a certificate from an appropriate officer of the
Company which states that the proposed supplement or amendment is in compliance
with the terms of this Section 27, the Rights Agent shall execute such
supplement or amendment. Notwithstanding anything contained in this Agreement to
the contrary, no supplement or amendment shall be made which changes the
Redemption Price, the Final Expiration Date, the Purchase Price or the number of
one one-hundredths of a share of Preferred Stock for which a Right is
exercisable. Prior to the Distribution Date, the interests of the holders of
Rights shall be deemed coincident with the interests of the holders of Common
Stock.

        Section 28. Successors.  All the covenants and provisions of this
                    ----------
Agreement by or for the benefit of the Company or the Rights Agent shall bind
and inure to the benefit of their respective successors and assigns hereunder.

        Section 29.  Determinations and Actions by the Board of Directors, etc.
                     ---------------------------------------------------------
For all purposes of this Agreement, any calculation of the number of shares
of Common Stock outstanding at any particular time, including for purposes of
determining the particular percentage of such outstanding shares of Common Stock
of which any Person is the Beneficial Owner, shall be made in accordance with
the provisions of the last sentence of Rule 13d-3(d)(l)(i) of the General Rules
and Regulations under the Exchange Act.  The Board (with, where specifically
provided for herein, the concurrence of the Continuing Directors) shall have the
exclusive power and authority to administer this Agreement and to exercise all
rights and powers specifically granted to the Board (with, where specifically
provided for herein, the concurrence of the Continuing Directors) or to the
Company, or as may be necessary or advisable in the administration of this
Agreement, including, without limitation, the right and power to (i) interpret
the provisions of this Agreement, and (ii) make all determinations deemed
necessary 
<PAGE>
 
or advisable for the administration of this Agreement (including a determination
to redeem or not redeem the Rights, to declare that a Person is an Adverse
Person or to amend the Agreement). All such actions, calculations,
interpretations and determinations (including, for purposes of clause (y) below,
all omissions with respect to the foregoing) which are done or made by the Board
(with, where specifically provided for herein, the concurrence of the Continuing
Directors) in good faith, shall (x) be final, conclusive and binding on the
Company, the Rights Agent, the holders of the Rights and all other parties, and
(y) not subject any member of the Board of Directors of the Company to any
liability to the holders of the Rights.

        Section 30. Benefits of this Agreement. Nothing in this Agreement shall
                    --------------------------
be construed to give to any Person other than the Company, the Rights Agent and
the registered holders of the Rights Certificates (and, prior to the
Distribution Date, registered holders of the Common Stock) any legal or
equitable right, remedy or claim under this Agreement; but this Agreement shall
be for the sole and exclusive benefit of the Company, the Rights Agent and the
registered holders of the Rights Certificates (and, prior to the Distribution
Date, registered holders of the Common Stock).

        Section 31. Severability .  If any term, provision, covenant or 
                    ------------
restriction of this Agreement is held by a court of competent jurisdiction or
other authority to be invalid, void or unenforceable, the remainder of the
terms, provisions, covenants and restrictions of this Agreement shall remain in
full force and effect and shall in no way be affected, impaired or invalidated,
provided, however, that notwithstanding anything in this Agreement to the 
--------  -------      
contrary, if any such term, provision, covenant or restriction is held by such
court or authority to be invalid, void or unenforceable and the Continuing
Directors determine in their good faith judgment that severing the invalid
language from this Agreement would materially and adversely affect the purpose
or effect of this Agreement, the right of redemption set forth in Section 23
hereof shall be reinstated and shall not expire until the close of business on
the tenth day following the date of such determination by the Continuing
Directors. Without limiting the foregoing, if any provision requiring that a
determination made by less than the entire Board is held by a court of competent
jurisdiction or other authority to be invalid, void or unenforceable, such
determination shall then be made by the entire Board.

        Section 32. Governing Law.  This Agreement, each Right and each Rights
                    -------------
Certificate issued hereunder 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 made
and to be performed entirely within such State.

        Section 33.  Counterparts. This Agreement may be executed in any number
                     ------------
of counterparts and each of such counterparts shall for all purposes be deemed
to be an original, and all such counterparts shall together constitute but one
and the same instrument.

        Section 34. Descriptive Headings. Descriptive headings of the several
                    --------------------
Sections of this Agreement are inserted for convenience only and shall not
control or affect the meaning or construction of any of the provisions hereof.



             [THE REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK]
<PAGE>
 
          IN WITNESS WHEREOF, the parties hereto have caused this Rights
Agreement to be duly executed and their respective corporate seals to be
hereunto affixed and attested, all as of the day and year first above written.



Attest:                                         PERSEPTIVE BIOSYSTEMS, INC.



By:/s/ Rufus C. King                            By:/s/ Noubar B. Afeyan
   --------------------                            -------------------------
   Name:  Rufus C. King                            Name:  Noubar B. Afeyan
   Title:   Assistant Secretary                    Title:  President and Chief
                                                            Executive Officer



Attest:                                         AMERICAN STOCK TRANSFER &
                                                  TRUST COMPANY



By:/s/ Susan Silber                              By:/s/ Herbert J. Lemmer
   ----------------------                           --------------------------
   Name:  Susan Silber                              Name:  Herbert J. Lemmer
   Title:  Assistant Secretary                      Title:  Vice President
<PAGE>
 
                      AMENDMENT NO. 1 TO RIGHTS AGREEMENT
                      -----------------------------------
                                        



     AMENDMENT NO. 1, dated as of September 27, 1995 (this "Amendment"), to the
                                                            ---------          
RIGHTS AGREEMENT, dated as of March 1, 1995 (the "Agreement"), between
                                                  ---------           
PERSEPTIVE BIOSYSTEMS, INC., a Delaware corporation (the "Company"), and
                                                          -------       
AMERICAN STOCK TRANSFER & TRUST COMPANY, as Rights Agent.



                              W I T N E S S E T H:



     WHEREAS, on February 23, 1995, the Board of Directors of the Company (the
                                                                              
"Board") authorized the execution of the Agreement pursuant to which certain
------                                                                      
rights to purchase one one-hundredth of a share of the Company's Series B Junior
Participating Preferred Stock have been distributed;

     WHEREAS, pursuant to Section 27 of the Agreement, the Company may amend the
Agreement at any time prior to the Final Amendment Date, as defined therein.

     WHEREAS, on September 22, 1995 the Board authorized the amendment of the
Agreement to correct certain definitional and typographical errors;

     NOW, THEREFORE, in consideration of the premises and the mutual agreements
herein set forth, the parties hereby agree as follows:

     1.   Section 11(a)(ii)(B) of the Agreement is hereby amended to replace the
words "the Beneficial Owner of 15% or more of the shares of Common Stock then
outstanding" appearing therein with the words "an Acquiring Person."

     2.   Section 23(a) is hereby amended by deleting the word "If" before the
word "following" at the beginning of the third sentence thereof.

     3.   Except as amended hereby, the Agreement shall continue in full force
and effect.
<PAGE>
 
     IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 1 to
the Rights Agreement to be duly executed and their respective corporate seals to
be hereunto affixed and attested, all as of the day and year first above
written.


Attest:                                         PERSEPTIVE BIOSYSTEMS, INC.
 
By:/s/ Rufus C. King                            By:/s/ Noubar B. Afeyan
   ------------------------                        ---------------------------
   Name: Rufus C. King                             Name:  Noubar B. Afeyan
   Title:  Assistant Secretary                     Title:  President and Chief
                                                           Executive Officer



Attest:
                                                AMERICAN STOCK TRANSFER & 
                                                TRUST COMPANY
 
By:/s/ Susan Silber                             By:/s/ Herbert J. Lemmer
   ------------------------                        ----------------------------
Name:  Susan Silber                                Name:  Herbert J. Lemmer
Title:  Assistant Secretary                        Title:  Vice President
<PAGE>
 
                      AMENDMENT NO. 2 TO RIGHTS AGREEMENT
                      -----------------------------------
                                        

     AMENDMENT NO. 2, dated as of August 23, 1997 (this "Amendment"), to the
                                                         ---------          
RIGHTS AGREEMENT, dated as of March 1, 1995, as amended on September 27, 1995
(the "Agreement"), between PERSEPTIVE BIOSYSTEMS, INC., a Delaware corporation
      ---------                                                               
(the "Company"), and AMERICAN STOCK TRANSFER & TRUST COMPANY, as Rights Agent.
      -------                                                                 


                              W I T N E S S E T H:


     WHEREAS, on February 23, 1995, the Board of Directors of the Company (the
                                                                              
"Board") authorized the execution of the Agreement pursuant to which certain
------                                                                      
rights to purchase one one-hundredth of a share of the Company's Series B Junior
Participating Preferred Stock have been distributed;


     WHEREAS, pursuant to Section 27 of the Agreement, the Company may amend the
Agreement at any time prior to the Final Amendment Date, as defined therein.


     WHEREAS, on August 23, 1997 the Board authorized the Amendment of the
Agreement in anticipation of approving (i) a merger (the "Merger") pursuant to
                                                          -----               
an Agreement and Plan of Merger with Perkin-Elmer Corporation (the "Parent") and
                                                                    ------      
a subsidiary of Parent (the "Sub") (the "Merger") and (ii) a Stock Option
                             ---         ------                          
Agreement with Parent;


     NOW, THEREFORE, in consideration of the premises and the mutual agreements
herein set forth, the parties hereby agree as follows:

     1.   Notwithstanding anything to the contrary in the Agreement, neither
Parent nor Sub will become an "Acquiring Person" or an "Adverse Person" and no
"Triggering Event", "Stock Acquisition Date" or "Distribution Date" (as such
terms are defined in the Agreement) will occur as a result of the approval,
execution or delivery of an Agreement and Plan of Merger (the "Merger
                                                               ------
Agreement") among the Company, Parent and Sub which has been approved by the
---------
Board of Directors or a Stock Option Agreement (the "Stock Option Agreement")
                                                     ----------------------  
granted to Parent by the Board of Directors, or the consummation of a merger
pursuant to the Merger Agreement or the acquisition of shares of Company Common
Stock by Parent pursuant to the Stock Option Agreement.


     2.   Parent and Sub are third party beneficiaries of this Amendment and the
terms of this Amendment shall not be withdrawn, amended or otherwise modified
without their written consent.


     3.   Except as amended hereby, the Agreement shall continue in full force
and effect.
<PAGE>
 
     IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 2 to
the Rights Agreement to be duly executed and their respective corporate seals to
be hereunto affixed and attested, all as of the day and year first above
written.


Attest:
                                               PERSEPTIVE BIOSYSTEMS, INC.
 
                                               By:/s/ Noubar B. Afeyan
By:_______________________                        --------------------------
Name:                                          Name:  Noubar B. Afeyan
Title:                                         Title:  President and Chief
                                                        Executive Officer

Attest:

                                               AMERICAN STOCK TRANSFER & 
                                                 TRUST COMPANY
 
By:/s/ Gail Domenech                           By:/s/ Paula Carappoli
   ------------------------                       -------------------------
Name: Gail Domenech                               Name: Paula Carappoli
Title: Executive Assistant                        Title: Vice President