RGISTRATION RIGHTS AGREEMENT


     THIS REGISTRATION RIGHTS AGREEMENT (this "Agreement"), dated as of March 1,
2000 (the "Agreement"),  is made by and between VerticalBuyer,  Inc., a Delaware
corporation   ("VerticalBuyer")  and  CSP  Inc.,  a  Massachusetts   corporation
("CSPI").

     WHEREAS,   in  connection  with  the  Securities  Purchase  and  Facilities
Agreement dated March 1, 2000.  between CSPI and VerticalBuyer  (the "Securities
and Facilities Agreement"), VerticalBuyer has agreed, upon the terms and subject
to the conditions of said Securities and Facilities Agreement, to issue and sell
to CSPI 2,000,000 shares of  VerticalBuyer's  common stock, par value $0.001 per
share  (the  "Shares"),  together  with  common  stock  purchase  warrants  (the
"Warrants") in three classes to purchase in the aggregate  3,000,000  additional
Shares; and

     WHEREAS,  in  connection  with  the  sale  of the  Shares  to  CSPI,  it is
contemplated that CSPI will distribute  approximately  700,000 Shares ratably to
its stockholders; and

     WHEREAS,  Vertical Buyer has agreed to issue 75,000 Warrants ratably to all
the holders of options to purchase CSPI common stock; and

     WHEREAS,  to induce CSPI to execute and deliver the Securities Purchase and
Facilities  Agreement,  VerticalBuyer has agreed to provide certain registration
rights  under  the  Securities  Act of  1933,  as  amended,  and the  rules  and
regulations  thereunder,  or any similar  successor statute  (collectively,  the
"1933 Act"),  and applicable state securities laws with respect to the Shares as
follows:

     (a)  the resale of 2,000,000 Shares privately placed to CSPI including

     (b)  the proposed  distribution of  approximately  700,000 Shares to CSPI's
          stockholders

     (c)  the issuance and resale of 3,000,000 Shares underlying the Warrants

     (d)  the issuance of up to 75,000 Warrants to the option holders of CSPI

     (e)  the issuance of up to 75,000 Shares  underlying the Warrants issued to
          the option holders of CSPI

     NOW,  THEREFORE,  in consideration of the premises and the mutual covenants
contained  herein and other good and  valuable  consideration,  the  receipt and
sufficiency  of which are hereby  acknowledged,  VerticalBuyer  and CSPI  hereby
agree as follows:

1.   Definitions. Capitalized terms used herein and not otherwise defined herein
     shall  have  the  respective  meanings  set  forth  in the  Securities  and
     Facilities Agreement. As used in this Agreement,  the following terms shall
     have the following meanings:

     (a)  "Registrable Securities" means the Shares and Warrants issued or to be
          issued by VerticalBuyer in connection with the following transactions:

          (i)  the resale of 2,000,000 Shares privately placed to CSPI including


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          (ii) the proposed  distribution  of  approximately  700,000  Shares to
               CSPI's stockholders;

          (iii)the  issuance  and  resale of  3,000,000  Shares  underlying  the
               Warrants;

          (iv) the  issuance of up to 75,000  Warrants to the option  holders of
               CSPI;

          (v)  the  issuance  of up to 75,000  Shares  underlying  the  Warrants
               issued to the option holders of CSPI; and

          (vi) any Shares issued as "late  registration  payments" as defined in
               paragraph 2(c).

     (b)  "Registration  Period"  means  the  period  between  the  date of this
          Agreement  and  the  earlier  of (i)  the  date  on  which  all of the
          Registrable  Securities  have  been  sold and no  further  Registrable
          Securities may be issued in the future,  or (ii) the date on which all
          the  Registrable  Securities (in the opinion of CSPI's counsel) may be
          immediately sold without registration.

     (c)  "Registration Statement" means a registration statement filed with the
          Securities and Exchange Commission (the "SEC") under the 1933 Act.

     (d)  The terms  "register,"  "registered,"  and  "registration"  refer to a
          registration   effected  by  preparing  and  filing  the  Registration
          Statement  in  compliance  with the 1933 Act and  pursuant to Rule 415
          under  the 1933  Act or any  successor  rule  providing  for  offering
          securities on a continuous basis ("Rule 415") and applicable rules and
          regulations   thereunder,   and  the   declaration   or   ordering  of
          effectiveness of such Registration Statement by the SEC.

2.   Registration.

     (a)  Mandatory  Registration.  VerticalBuyer  will  file  the  Registration
          Statement on Form SB-2 (or if Form SB-2 is not then available, on such
          form of  registration  statement  as is then  available  to  effect  a
          registration  of  all  the  Registrable   Securities)   with  the  SEC
          registering the  Registrable  Securities for resale within thirty (30)
          business days of the this Agreement. To the extent allowable under the
          1933 Act, the  Registration  Statement  shall  include the  securities
          listed in paragraph  101(a) and such  additional  Shares as may become
          issuable  upon  exercise  of  the  Warrants  (i) to  prevent  dilution
          resulting from stock splits, stock dividends or similar  transactions,
          or (ii) by reason of changes in the exercise  price of the Warrants in
          accordance  with the terms thereof.  VerticalBuyer  shall use its best
          efforts to cause the Registration  Statement to be declared  effective
          by the SEC as soon as  practicable  after  filing  and in any event no
          later than the  ninetieth  (90th)  business day  following the Closing
          Date (the "Required Effective Date"). Such best efforts shall include,
          but not be limited to,  promptly  responding to all comments  received
          from the staff of the SEC. Should  VerticalBuyer  receive notification
          from the SEC that the Registration Statement will receive no action or
          no review from the SEC,  VerticalBuyer  shall cause such  Registration
          Statement to become  effective  within seven (7) business days of such
          SEC notification.  Once declared  effective by the SEC,  VerticalBuyer
          shall cause the Registration  Statement to remain effective throughout
          the Registration Period.

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<PAGE>

     (c)  Late Registration  Payments.  If the Registration  Statement  required
          pursuant to paragraph  2(a) above has not been  declared  effective by
          the  Required  Effective  Date,   VerticalBuyer  will  issue  to  CSPI
          additional  Shares equal to one percent (1%) of the  purchased  Shares
          for each full month following the Required Effective Date,  continuing
          through the date the Registration  Statement is declared  effective by
          the SEC. The Late  Registration  Share  issuance will be prorated on a
          daily basis for partial  months and will be issued to CSPI within five
          (5) business days  following the  effective  date of the  Registration
          Statement.

          The obligations of VerticalBuyer under this paragraph 2(d) will expire
          upon the earlier of the effectiveness of the Registration Statement or
          when all of the  Registrable  Securities may be sold by under Rule 144
          under the 1933 Act without being subject to any volume restrictions.

3.   Additional   Obligations   of   VerticalBuyer.   In  connection   with  the
     registration of the Registrable  Securities,  VerticalBuyer  shall have the
     following additional obligations:

     (a)  VerticalBuyer shall keep the Registration Statement effective pursuant
          to Rule 415 under the 1933 Act at all times  during  the  Registration
          Period.

     (b)  The Registration Statement shall not contain any untrue statement of a
          material  fact or omit to state a material  fact required to be stated
          therein,  or necessary to make the statements therein, in light of the
          circumstances  in which they were made, not misleading.  VerticalBuyer
          shall  prepare  and  file  with  the SEC  such  amendments  (including
          post-effective   amendments)  and  supplements  to  the   Registration
          Statement and the prospectus used in connection with the  Registration
          Statement  as  may  be  necessary  to  permit  sales  pursuant  to the
          Registration  Statement at all times during the  Registration  Period,
          and, during such period,  shall comply with the provisions of the 1933
          Act with respect to the disposition of all  Registrable  Securities of
          VerticalBuyer   covered  by  the  Registration   Statement  until  the
          termination of the Registration  Period, or, if earlier,  such time as
          all  of  such  Registrable   Securities  which  require  an  effective
          registration statement under the 1933 Act have been disposed of.

     (c)  VerticalBuyer shall furnish to CSPI and its legal counsel (i) promptly
          after the same is prepared  and publicly  distributed,  filed with the
          SEC or  received  by  VerticalBuyer,  one  copy  of  the  Registration
          Statement and any amendment thereto;  each preliminary  prospectus and
          final prospectus and each amendment or supplement thereto, each letter
          written by or on behalf of  VerticalBuyer  to the SEC and each item of
          correspondence  from the SEC or the  staff of the  SEC,  in each  case
          relating  to such  Registration  Statement;  and (ii)  such  number of
          copies of a prospectus,  including a preliminary  prospectus,  and all
          amendments and supplements  thereto,  and such other documents as CSPI
          may reasonably  request in order to facilitate the  disposition of the
          Registrable Securities.

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<PAGE>

     (d)  VerticalBuyer  shall use its best  efforts to (i) register and qualify
          the Registrable Securities covered by the Registration Statement under
          such other  securities or blue sky laws of such  jurisdictions as CSPI
          reasonably requests, (ii) prepare and file in those jurisdictions such
          amendments  (including  post-effective  amendments) and supplements to
          such  registrations and qualifications as may be necessary to maintain
          the effectiveness  thereof during the Registration  Period, (iii) take
          such other actions as may be necessary to maintain such  registrations
          and  qualifications  in effect at all times  during  the  Registration
          Period,  and (iv)  take all  other  actions  reasonably  necessary  or
          advisable  to  qualify  the  Registrable  Securities  for sale in such
          jurisdictions.  Notwithstanding the foregoing provision, VerticalBuyer
          shall  not be  required  in  connection  therewith  or as a  condition
          thereto to (i)  qualify to do business  in any  jurisdiction  where it
          would not  otherwise  be required  to qualify but for this  paragraph,
          subject  itself to general  taxation in any such  jurisdiction,  (iii)
          file a general consent to service of process in any such jurisdiction,
          (iv) provide any undertakings that cause material expense or burden to
          VerticalBuyer,  or (v) make any change in its charter or bylaws, which
          in each case the Board of Directors of VerticalBuyer  determines to be
          contrary to the best interests of VerticalBuyer and its stockholders.

     (e)  VerticalBuyer shall notify CSPI of the happening of any event of which
          VerticalBuyer  has  knowledge  as a  result  of which  the  prospectus
          included in the  Registration  Statement as then in effect includes an
          untrue  statement of a material fact or omits to state a material fact
          required  to be stated  therein or  necessary  to make the  statements
          therein, in light of the circumstances under which they were made, not
          misleading  (a  "Suspension  Event").  VerticalBuyer  shall  make such
          notification as promptly as practicable  after  VerticalBuyer  becomes
          aware of such  Suspension  Event,  shall promptly use its best efforts
          (but in any event  within  five (5) days) to prepare a  supplement  or
          amendment  to  the  Registration  Statement  to  correct  such  untrue
          statement  or omission,  and shall  deliver a number of copies of such
          supplement  or  amendment  to  CSPI as CSPI  may  reasonably  request.
          VerticalBuyer  shall  promptly  notify  CSPI as soon as the use of the
          Registration Statement may be resumed.

     (f)  VerticalBuyer  shall use its best  efforts to prevent the  issuance of
          any stop order or other  suspension of effectiveness of a Registration
          Statement and, if such an order is issued,  shall use its best efforts
          to obtain the  withdrawal of such order at the earliest  possible time
          and to notify CSPI of the  issuance  of such order and the  resolution
          thereof.

     (g)  VerticalBuyer  shall  cooperate  with CSPI to  facilitate  the  timely
          preparation and delivery of certificates  (not bearing any restrictive
          legends) representing Registrable Securities to be offered pursuant to
          the Registration  Statement and enable such certificates to be in such
          denominations  or amounts as the case may be, and  registered  in such
          names as CSPI may reasonably request; and, within one (1) business day
          after a Registration  Statement which includes Registrable  Securities
          is ordered  effective by the SEC,  VerticalBuyer  shall  deliver,  and
          shall cause legal counsel selected by VerticalBuyer to deliver, to the
          transfer  agent for the  Registrable  Securities  instructions  to the
          transfer agent to issue new stock certificates without a legend and an
          opinion  of such  counsel  that the  Shares  and  Warrants  have  been
          registered.

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<PAGE>

     (h)  VerticalBuyer  shall  promptly  prepare  and  file  with  the SEC such
          amendments (including post-effective  amendments) and supplements to a
          Registration  Statement and the prospectus used in connection with the
          Registration Statement as may be necessary in order to change the plan
          of distribution set forth in such Registration Statement.

     (i)  VerticalBuyer  shall  comply with all  applicable  laws related to the
          Registration  Statement  and offering and sale of  securities  and all
          applicable  rules  and  regulations  of  governmental  authorities  in
          connection therewith  (including,  without limitation,  the Securities
          Act and the Securities Exchange Act of 1934, as amended, and the rules
          and regulations promulgated by the SEC).

     (j)  VerticalBuyer  shall take all other reasonable actions as the CSPI may
          reasonably  request to  expedite  and  facilitate  disposition  of the
          Registrable Securities pursuant to the Registration Statement.

4.   Obligations of CSPI. In connection with the registration of the Registrable
     Securities, CSPI shall have the following obligations:

     (a)  CSPI will  cooperate  with  VerticalBuyer  as reasonably  requested by
          VerticalBuyer  in connection  with the  preparation  and filing of the
          Registration Statement hereunder.

     (b)  CSPI agrees that, upon receipt of any notice from VerticalBuyer of the
          happening  of any event of the kind  described in Section 3, CSPI will
          immediately discontinue disposition of Registrable Securities pursuant
          to the Registration  Statement  covering such  Registrable  Securities
          until  CSPI's  receipt  of the copies of the  supplemented  or amended
          prospectus.

5.   Expenses of Registration.  All reasonable  expenses  incurred in connection
     with registrations, filings or qualifications pursuant to Sections 2 and 3,
     including, without limitation, all registration, listing and qualifications
     fees,  printers and accounting fees, the fees and  disbursements of counsel
     for VerticalBuyer, and the reasonable fees and disbursements of one counsel
     selected by CSPI, shall be borne by VerticalBuyer.

6.   Indemnification.

     (a)  To the extent permitted by law,  VerticalBuyer will indemnify and hold
          harmless CSPI, its directors,  its officers,  each person, if any, who
          controls  the CSPI within the meaning of the 1933 Act or the  Exchange
          Act,  (each,  an "Indemnified  Person"),  against any losses,  claims,
          damages,  expenses or  liabilities  (joint or  several)  (collectively
          together with actions,  proceedings  or inquiries by any regulatory or
          self-regulatory  organization,  whether  commenced  or  threatened  in
          respect  thereof,  "Claims") to which any of them become subject under
          the 1933 Act, the Exchange  Act or  otherwise,  insofar as such Claims
          arise  out of or are  based  upon  any  of the  following  statements,
          omissions  or  violations  in  the  Registration   Statement,  or  any
          post-effective  amendment thereof, or any prospectus included therein:
          (i) any untrue  statement  or alleged  untrue  statement of a material
          fact  contained in the  Registration  Statement or any  post-effective
          amendment thereof or the omission or alleged omission to state therein
          a material fact required to be stated therein or necessary to make the


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<PAGE>

          statements  therein  not  misleading,  (ii) any  untrue  statement  or
          alleged  untrue   statement  of  a  material  fact  contained  in  any
          preliminary  prospectus  if used prior to the  effective  date of such
          Registration  Statement,  or  contained  in the final  prospectus  (as
          amended or supplemented,  if VerticalBuyer files any amendment thereof
          or  supplement  thereto  with  the  SEC) or the  omission  or  alleged
          omission to state  therein any  material  fact  necessary  to make the
          statements made therein, in light of the circumstances under which the
          statements  therein were made, not misleading,  or (iii) any violation
          or alleged  violation by  VerticalBuyer  of the 1933 Act, the Exchange
          Act  or  any  other  law,   including  without  limitation  any  state
          securities  law or any rule or regulation  thereunder  (the matters in
          the  foregoing   clauses  (i)  through   (iii)  being,   collectively,
          "Violations"). VerticalBuyer shall reimburse CSPI and each Indemnified
          Person,  promptly  as  such  expenses  are  incurred  and  are due and
          payable,  for any legal fees or other reasonable  expenses incurred by
          them in  connection  with  investigating  or defending any such Claim.
          Notwithstanding   anything  to  the  contrary  contained  herein,  the
          indemnification  agreement contained in this paragraph 6(a): (A) shall
          not apply to a Claim  arising out of or based upon a  Violation  which
          occurs in reliance upon and in conformity with  information  furnished
          in writing to  VerticalBuyer  by any Indemnified  Person expressly for
          use in connection with the preparation of the  Registration  Statement
          or  any  such  amendment  thereof  or  supplement   thereto,  if  such
          prospectus  was timely made  available  by  VerticalBuyer  pursuant to
          paragraph 3(c) hereof; (B) with respect to any preliminary  prospectus
          shall not inure to the benefit of any Indemnified  Party from whom the
          person  asserting any such Claim purchased the Registrable  Securities
          that  are  the  subject  thereof  (or to  the  benefit  of any  person
          controlling  such  person)  if the untrue  statement  or  omission  of
          material fact contained in the preliminary prospectus was corrected on
          a timely basis in the prospectus, as then amended or supplemented,  if
          such prospectus was timely made available by VerticalBuyer pursuant to
          paragraph 3(c) hereof;  and the Indemnified Party was promptly advised
          in writing not to use the incorrect prospectus prior to the use giving
          rise to a Violation and such Indemnified Party,  notwithstanding  such
          notice,  used it (C) shall not apply to amounts paid in  settlement of
          any Claim if such  settlement  is effected  without the prior  written
          consent of  VerticalBuyer,  which  consent  shall not be  unreasonably
          withheld.  Such  indemnity  shall  remain  in full  force  and  effect
          regardless  of  any  investigation   made  by  or  on  behalf  of  the
          Indemnified  Persons and shall survive the transfer of the Registrable
          Securities pursuant to Section 9.

     (b)  In  connection  with  any  Registration  Statement  in  which  CSPI is
          participating,  CSPI will  indemnify  and hold  harmless,  to the same
          extent  and  in  the  same  manner  set  forth  in   paragraph   6(a),
          VerticalBuyer,  each of its directors,  each of its officers who signs
          the  Registration  Statement,   each  person,  if  any,  who  controls
          VerticalBuyer  within the meaning of the 1933 Act or the Exchange Act,
          and  any  other  stockholder   selling  securities   pursuant  to  the
          Registration  Statement  or any of its  directors  or  officers or any
          person who controls  such  stockholder  within the meaning of the 1933
          Act or the Exchange Act (collectively and together with an Indemnified
          Person,  an  "Indemnified  Party"),  against any Claim to which any of
          them may  become  subject,  under the 1933 Act,  the  Exchange  Act or
          otherwise,  insofar as such  Claim  arises out of or is based upon any
          Violation,  in each case to the extent (and only to the  extent)  that
          such Violation  occurs in reliance upon and in conformity with written
          information  furnished to  VerticalBuyer  by CSPI expressly for use in
          connection with such Registration Statement,  and subject to paragraph
          6(c),  CSPI  will  promptly  reimburse  any  legal or  other  expenses
          (promptly  as  such   expenses  are  incurred  and  due  and  payable)
          reasonably   incurred  by  it  in  connection  with  investigating  or
          defending  any such  Claim;  provided,  however,  that  the  indemnity
          agreement  contained in this paragraph 6(b) shall not apply to amounts
          paid in settlement of any Claim if such settlement is effected without
          the  prior  written  consent  of  CSPI,  which  consent  shall  not be
          unreasonably withheld;  provided further,  however, that CSPI shall be



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          liable  under  this  Agreement  (including  this  paragraph  6(b)  and
          paragraph  7) for only that  amount of a Claim as does not  exceed the
          net  proceeds  actually  received  by CSPI as a result  of the sale of
          Registrable Securities pursuant to such Registration  Statement.  Such
          indemnity  shall  remain in full  force and effect  regardless  of any
          investigation made by or on behalf of such Indemnified Party and shall
          survive the transfer of the Registrable Securities pursuant to Section
          9.  Notwithstanding  anything to the contrary  contained  herein,  the
          indemnification  agreement  contained  in  this  paragraph  6(b)  with
          respect to any preliminary  prospectus  shall not inure to the benefit
          of any  Indemnified  Party if the  untrue  statement  or  omission  of
          material fact contained in the preliminary prospectus was corrected on
          a timely basis in the prospectus, as then amended or supplemented, and
          the Indemnified Party failed to utilize such corrected prospectus.

     (c)  Promptly after receipt by an Indemnified  Person or Indemnified  Party
          under  this  Section  6 of notice of the  commencement  of any  action
          (including  any  governmental  action),  such  Indemnified  Person  or
          Indemnified  Party  shall,  if a Claim in  respect  thereof is to made
          against any  indemnifying  party under this  Section 6, deliver to the
          indemnifying  party a written notice of the  commencement  thereof and
          this  indemnifying  party shall have the right to participate in, and,
          to the extent the  indemnifying  party so  desires,  jointly  with any
          other indemnifying  party similarly noticed,  to assume control of the
          defense thereof with counsel mutually satisfactory to the indemnifying
          parties and the Indemnified  Person or the  Indemnified  Party, as the
          case may be; provided,  however,  that such  indemnifying  party shall
          diligently  pursue such defense;  and provided,  further,  that if the
          defendants in any such action include both the  Indemnified  Person or
          Party and the indemnifying  party, and the Indemnified Person or Party
          shall have reasonably  concluded that a conflict may arise between the
          positions  of the  indemnifying  party and the  Indemnified  Person or
          Party in  conducting  the defense of any such action or that there may
          be legal  defenses  available to it and/or other  indemnified  parties
          which are  different  from or  additional  to those  available  to the
          indemnifying  party,  then the Indemnified  Person or Party shall have
          the right to retain separate  counsel,  the fees and expenses of which
          shall be paid by the indemnifying party, to assume such legal defenses
          and to otherwise  participate  in the defense of such action on behalf
          of such Indemnified  Person or Party. In case an Indemnified Person or
          Party shall have retained  separate counsel pursuant to the proviso in
          the immediately  preceding sentence,  the indemnifying party shall not
          be liable for the expenses of more than one such separate counsel. The
          failure to deliver written notice to the  indemnifying  party within a
          reasonable  time of the  commencement  of any such  action  shall  not
          relieve such  indemnifying  party of any liability to the  Indemnified
          Person or Indemnified Party under this Section 6, except to the extent
          that the  indemnifying  party is  prejudiced  in its ability to defend
          such action. The  indemnification  required by this Section 6 shall be
          made by periodic  payments of the amount  thereof during the course of
          the  investigation  or  defense,  as such  expense,  loss,  damage  or
          liability is incurred and is due and payable.

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7.   Contribution.  If the indemnification  provided for in Section 6 is for any
     reason held by a court of competent  jurisdiction  to be  unavailable to or
     otherwise  insufficient to hold harmless an Indemnified  Person or Party in
     respect of any losses, claims, damages, liabilities or expenses referred to
     therein,  then each  indemnifying  party shall  contribute to the aggregate
     amount paid or payable by such Indemnified Person or Party, as incurred, as
     a result of any losses, claims,  damages,  liabilities or expenses referred
     to therein (i) in such proportion as is appropriate to reflect the relative
     benefits received by VerticalBuyer, on the one hand, and CSPI, on the other
     hand,  from the  original  issuance  of the common  stock of  VerticalBuyer
     (including  the  common  stock  issued or  issuable  upon the  exercise  of
     warrants)  pursuant to that  certain  Securities  Purchase  and  Facilities
     Agreement  of even date  herewith,  or (ii) if the  allocation  provided by
     clause (i) is not  permitted by  applicable  law, in such  proportion as is
     appropriate to reflect not only the relative benefits referred to in clause
     (i) but also the  relative  fault of  VerticalBuyer,  on the one hand,  and
     CSPI, on the other hand, in connection  with the statements or omissions or
     inaccuracies  in the  Registration  Statement or any  preliminary  or final
     prospectus therein, or in the representations and warranties herein,  which
     resulted in such losses, claims, damages,  liabilities or expenses, as well
     as any other  relevant  equitable  considerations.  The  relative  fault of
     VerticalBuyer,  on the one hand,  and CSPI,  on the  other  hand,  shall be
     determined by reference to, among other things,  whether any such untrue or
     alleged untrue statement of a material fact or omission or alleged omission
     to state a  material  fact or any such  inaccurate  or  alleged  inaccurate
     representation   or   warranty   relates   to   information   supplied   by
     VerticalBuyer,  on the one  hand,  or  CSPI,  on the  other  hand,  and the
     parties' relative intent, knowledge,  access to information and opportunity
     to  correct or prevent  such  statement  or  omission.  The amount  paid or
     payable by a party as a result of the losses, claims, damages,  liabilities
     and expenses  referred to above shall be deemed to include,  subject to the
     limitations  set forth in Section  6, any legal or other  fees or  expenses
     reasonably  incurred  by such party in  connection  with  investigating  or
     defending any action or claim.  The  provisions set forth in Section 6 with
     respect to notice of  commencement of any action shall apply if a claim for
     contribution is to be made under this Section 7; provided, however, that no
     additional  notice  shall be required  with respect to any action for which
     notice has been given  under  Section 6 for  purposes  of  indemnification.
     Notwithstanding  the  provisions  of this  Section  7, no person  guilty of
     fraudulent  misrepresentation (within the meaning of paragraph 11(f) of the
     Securities Act) shall be entitled to  contribution  from any person who was
     not  guilty of such  fraudulent  misrepresentation.  For  purposes  of this
     Section 7, each officer and  employee of CSPI and each person,  if any, who
     controls CSPI within the meaning of the Securities Act and the Exchange Act
     shall have the same rights to  contribution  as CSPI,  and each director of
     VerticalBuyer,  each officer of  VerticalBuyer  who signed the Registration
     Statement,  and each person, if any, who controls  VerticalBuyer within the
     meaning  of the  Securities  Act and the  Exchange  Act shall have the same
     rights to contribution as VerticalBuyer.

8.   Assignment of Registration Rights. The rights of CSPI hereunder,  including
     the right to have  VerticalBuyer  register  the  Shares,  Warrants  and the
     Shares  underlying  the  Warrants  pursuant  to  this  Agreement  shall  be
     automatically  assigned  to  transferees  of  all or any  portion  of  such
     securities  only if such transfer  shall have been made in accordance  with
     the applicable requirements of the Securities and Facilities Agreement.

9.   Amendment of  Registration  Rights.  Provisions  of this  Agreement  may be
     amended and the observance  thereof may be waived (either generally or in a
     particular  instance and either  retroactively or prospectively)  only with
     the written  consent of  VerticalBuyer  and CSPI.  Any  amendment or waiver
     effected in accordance  with this Section 10 shall be binding upon CSPI and
     VerticalBuyer.  Notwithstanding the foregoing, no amendment or waiver shall
     retroactively affect CSPI without its consent.

                                       8
<PAGE>

10.  Miscellaneous.

     (a)  Conflicting Instructions.  A person or entity is deemed to be a holder
          of  Registrable  Securities  whenever  such  person or entity  owns of
          record  such  Registrable   Securities.   If  VerticalBuyer   receives
          conflicting  instructions,  notices  or  elections  from  two or  more
          persons or entities with respect to the same  Registrable  Securities,
          VerticalBuyer  shall  act upon the  basis of  instructions,  notice or
          election  received  from  the  registered  owner  of such  Registrable
          Securities.

     (b)  Notices. Any notices required or permitted to be given under the terms
          of this Agreement  shall be sent by certified or registered mail (with
          return  receipt  requested)  or  delivered  personally  or by  courier
          (including a nationally  recognized  overnight delivery service) or by
          facsimile transmission.  Any notice so given shall be deemed effective
          three days after being  deposited in the U.S. Mail, or upon receipt if
          delivered personally or by courier or facsimile transmission,  in each
          case  addressed  to a party at the  following  address  or such  other
          address as each such Party  furnishes to the other in accordance  with
          this paragraph 12(b):

         If to VerticalBuyer:
         Tim Rosen,
         President
         VerticalBuyer, Inc.
         c/o Donahue & Associates
         83 Meadow Road West
         Trumbull, Connecticut 06611

         If to CSPI:
         Alexander Lupinetti
         Chief Executive Officer
         40 Linnell Circle
         Billerica, MA 01821

         with a copy to
         Dean F. Hanley, Esquire
         Foley, Hoag & Eliot LLP
         One Post Office Square
         Boston, Massachusetts 02109
         Phone: 617-832-1000
         Facsimile: 617-832-7000


     (c)  Waiver.  Failure of any party to  exercise  any right or remedy  under
          this  Agreement or otherwise,  or delay by a party in exercising  such
          right or remedy, shall not operate as a waiver thereof.

     (d)  Governing Law. This  Agreement  shall be governed by and construed and
          enforced in accordance with the substantive  laws of The  Commonwealth
          of  Massachusetts  without  regard to its  principles  of conflicts of
          laws,  and any  disputes  arising  hereunder  will be  adjudicated  in
          federal or state court situated therein. Each party hereto consents to
          venue  in  Massachusetts  and  to  the  personal  and  subject  matter
          jurisdiction of said courts and, to the extent permitted by applicable
          law,  agrees to waive any objection as to such  jurisdiction or venue,
          and agrees not to assert any defense based on lack of  jurisdiction or
          venue.

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<PAGE>

     (e)  Severability.  In the event that any  provision  of this  Agreement is
          invalid or unenforceable  under any applicable statute or rule of law,
          then such provision shall be deemed  inoperative to the extent that it
          may conflict  therewith  and shall be deemed  modified to conform with
          such  statute or rule of law.  Any  provision  hereof  which may prove
          invalid or  unenforceable  under any law shall not affect the validity
          or enforceability of any other provision hereof.

     (f)  Entire  Agreement.  This  Agreement,  the  Securities  and  Facilities
          Agreement,  and the Warrants  (including  all  schedules  and exhibits
          thereto)  constitute  the  entire  agreement  among the  Parties  with
          respect  to the  subject  matter  hereof  and  thereof.  There  are no
          restrictions,  promises, warranties or undertakings,  other than those
          set forth or referred to herein or therein.  This Agreement supersedes
          all prior agreements and understandings  among the parties hereto with
          respect to the subject matter hereof.

     (g)  Successors  and  Assigns.  Subject  to the  requirements  of Section 9
          hereof,  this  Agreement  shall inure to the benefit of and be binding
          upon the successors and assigns of each of the Parties.

     (h)  Use of Pronouns.  All pronouns and any variations thereof refer to the
          masculine,  feminine or neuter, singular or plural, as the context may
          require.

     (i)  Headings.  The  headings  and  subheadings  in the  Agreement  are for
          convenience of reference only and shall not limit or otherwise  affect
          the meaning hereof.

     (j)  Counterparts.   This   Agreement  may  be  executed  in  two  or  more
          counterparts,  each of which  shall be deemed an  original  but all of
          which shall  constitute one and the same  agreement.  This  Agreement,
          once executed by Party,  may be delivered to the other party hereto by
          facsimile  transmission,  and facsimile signatures shall be binding on
          the parties hereto.

     (k)  Further Acts. Each Party shall do and perform, or cause to be done and
          performed,  all such  further acts and things,  and shall  execute and
          deliver  all such  other  agreements,  certificates,  instruments  and
          documents,  as the  other.  party may  reasonably  request in order to
          carry out the intent and accomplish the purposes of this Agreement and
          the consummation of the transactions contemplated hereby.

     (l)  Consents.  All  consents  and  other  determinations  to  be  made  by
          transferees pursuant to this Agreement shall be made by CSPI.

    IN WITNESS  WHEREOF,  the Parties  have caused  this  Agreement  to be duly
executed as of the date first above written.


                                    VERTICALBUYER, INC.

                                    By: /s/Tim Rosen
                                        -----------------------
                                            Tim Rosen,
                                            President

                                    CSP INC.

                                    By: /s/Alexander Lupinetti
                                        ----------------------
                                           Alexander Lupinetti,
                                           Chief Executive Officer




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