EXHIBIT 4.3
                         H.E.R.C. PRODUCTS INCORPORATED

                                AGENCY AGREEMENT


                                                     As of November 15, 1996



Perrin, Holden & Davenport Capital Corp.
17 John Street
3rd Floor
New York, New York 10038

Gentlemen:

         H.E.R.C.  Products  Incorporated,  a Delaware corporation  ("Company"),
proposes to offer for sale in a private placement ("Offering"), up to $1,500,000
in  aggregate  purchase  price of  shares  of  preferred  stock,  $.01 par value
("Preferred  Stock"), as more fully described in the Certificate of Designations
attached hereto as Exhibit A. The per-share offering price ("Offering Price") to
purchasers  ("Subscribers")  will be $10.00 and the stated  value will be $10.00
per share.

         The  Offering  will be made on a  "best  efforts,  minimum  $1,000,000,
maximum  $1,500,000 basis." The Preferred Stock will be sold only to "accredited
investors" in accordance  with Section 4(2) and/or 3(b) of the Securities Act of
1933, as amended ("Securities Act"), and Rules 501-506 of Regulation D ("Reg D")
promulgated thereunder.

         The  Subscribers  shall have the rights and be subject to the terms and
conditions  reflected  in the  subscription  agreement  to be  executed  by each
Subscriber  and  the  Company  (collectively,  the  "Subscription  Agreements"),
together with the exhibits thereto,  including, but not limited to the Company's
Annual  Report on Form 10-KSB for the fiscal year ended  December 31, 1995,  and
the  Company's  Quarterly  Report on Form  10-QSB for the fiscal  quarter  ended
September 30, 1996, and the Company's Proxy  Statement,  dated January 11, 1996,
and the Company's Prospectus, dated June 12, 1996, all of which together will be
referred  to herein as the  "Offering  Documents."  Perrin,  Holden &  Davenport
Capital Corp.  is sometimes  referred to herein as the  "Placement  Agent" or as
"PHD."

     6. Appointment of Placement Agent; The Offering.

     (a)  Appointment of Placement  Agent.  You are hereby  appointed  exclusive
Placement  Agent of the  Company  for the  purpose of  assisting  the Company in
finding qualified Subscribers. You hereby accept such agency and agree to assist
the  Company in finding  qualified  Subscribers.  You are hereby  authorized  to
engage, at your option, the services of other  broker-dealers who are members of
the National  Association of Securities Dealers,  Inc. ("NASD") to assist you in
soliciting  Subscribers and to remit to the  broker-dealers  all or a portion of
the commissions  payable to you under Section 4.3 hereof and the Placement Agent
Option issuable to you under Section 4.4 hereof, as you shall determine.




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     (b) Offering  Period;  Closings.  The offering period  ("Offering  Period")
shall  commence on November 15, 1996 and shall  continue until November 30, 1996
("Termination  Date"), unless extended by the Company and the Placement Agent to
a date not later than December 15, 1996,  without notice to  Subscribers.  If at
any time prior to the Termination Date, subscriptions for at least $1,000,000 in
aggregate  purchase  price for the shares of Preferred  Stock have been received
and accepted (and funds in payment have cleared),  then, upon the mutual consent
of the Company and the Placement Agent, a closing ("Initial Closing") shall take
place with respect to such accepted subscriptions and the Company shall continue
the Offering  until all the  Preferred  Stock is sold or the end of the Offering
Period,  whichever occurs first. After the Initial Closing,  subsequent closings
of Preferred Stock with respect to accepted  subscriptions may take place at any
time during the Offering  Period as mutually  determined  by the Company and the
Placement  Agent (the Initial  Closing and any  subsequent  closing will each be
referred to herein as a "Closing").  If subscriptions for at least $1,000,000 in
aggregate  purchase price for the shares of Preferred Stock are not received and
accepted (and funds in payment therefor  cleared) by the Termination  Date, then
the Offering will be terminated and all funds received from  Subscribers will be
returned, without interest and without any deduction.

     (c) Offering Documents. The Company will provide the Placement Agent with a
sufficient number of copies of the Offering  Documents for delivery to potential
Subscribers  and such other  information,  documents and  instruments  which the
Placement Agent deems  reasonably  necessary to act as placement agent hereunder
and to comply  with the rules,  regula  tions and  judicial  and  administrative
interpretations respecting compliance with applicable state and federal statutes
related to the Offering.

     (d)  Segregation of Funds.  Each  Subscriber for Preferred Stock shall wire
the purchase  price to a designated  account  maintained  by Attorneys  Graubard
Mollen & Miller.

     (e) No Firm Commitment.  The Company  understands and acknowledges that the
undertaking  by the Placement  Agent  pursuant to this  Agreement is not a "firm
commitment" offering and that the Placement Agent is not obligated in any way to
purchase or sell the Preferred Stock offered hereby.

     7.  Representations  and Warranties of the Company.  The Company represents
and  warrants  upon the  execution  of this  Agreement  and again at the Initial
Closing and any subsequent Closings as follows:

     (a)  Due  Incorporation  and  Qualification.  The  Company  has  been  duly
incorporated,  is validly existing and is in good standing under the laws of its
state of incorporation  and is duly qualified as a foreign  corporation  (except
where the failure to so qualify would not have a material  adverse effect on the
Company)  for  the  transaction  of  business  and is in good  standing  in each
jurisdiction  in which the ownership or leasing of its properties or the conduct
of its business requires such qualification.

     (b)  Authorized  Capital.  The Company is  authorized  to issue  40,000,000
shares of Common  Stock  and  1,000,000  shares  of  preferred  stock,  of which
6,356,487  shares of Common Stock and no shares of Preferred Stock are currently
issued and outstanding. All of the issued and outstanding shares of Common Stock
have  been  duly and  validly  authorized  and  issued  and are  fully  paid and
non-assessable.  The offers and sales of such outstanding shares of Common Stock
were at all relevant  times either  registered  under the Securities Act and the
applicable state securities or Blue Sky laws, or exempt from such registration.




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     (c)  Financial  Statements;  No Material  Adverse  Changes.  The  financial
statements  of the Company  included in the  Offering  Documents  ("Financials")
fairly present the consolidated  financial position and results of operations of
the Company at the dates thereof and for the periods covered thereby, subject to
year-end  adjustments and normal recurring accruals.  Other than as set forth on
the  September  30, 1996 balance  sheet  contained in the  Financials  ("Balance
Sheet"),  the Company has no material  liabilities or  obligations,  contingent,
direct,  indirect or otherwise,  except those incurred in the ordinary course of
business since the date of the Balance Sheet.  Except as otherwise stated in the
Offering  Documents or incurred in the ordinary course of the Company's business
since  September  30,  1996,  there has not been any  change  in the  condition,
financial or otherwise,  of the Company which could materially  adversely affect
its ability to conduct its operations as described in the Offering Documents.

     (d) No Pending Actions. There are no actions, suits,  proceedings,  claims,
hearings,  any investigations or inquiries before or by any court,  governmental
authority, tribunal or instrumentality (or to the Company's knowledge, any state
of facts which would give rise thereto), pending or, to the Company's knowledge,
threatened against the Company or involving the properties of the Company, which
might  result  in any  material  adverse  change  in the  business,  properties,
financial  position  or results of  operations  of the  Company,  or which might
adversely affect the  transactions or other acts  contemplated by this Agreement
or the validity or enforceability of this Agreement.

     (e) Private Offering Exemption.  Assuming that (i) a proper Form D is filed
in  accordance  with  Rule 503 of Reg D, (ii) that the offer and the sale of the
Preferred Stock by the Placement Agent is made in compliance with Rule 502(c) of
Reg D and (iii) that the  representations of the Subscribers in the Subscription
Agreements  signed  by them  are  true  and  correct  (which  facts  will not be
independently  verified  by the  Company),  the sale of  Preferred  Stock in the
Offering  is  exempt  from  registration  under  the  Securities  Act  and is in
compliance with Reg D.

     (f) Due  Authorization;  Consents.  The Company  has full right,  power and
authority to enter into this  Agreement,  the  Subscription  Agreements  and the
Placement  Agent  Option (as  defined in Section  4.4) and to perform all of its
obligations  hereunder  and  thereunder.   This  Agreement  has  been,  and  the
Subscription  Agreements  and Placement  Agent Option will be, duly  authorized,
executed  and  delivered  by the  Company.  The  execution  and delivery of this
Agreement has been, and the Subscription  Agreements and Placement Agent Option,
when executed and  delivered  will have been,  duly  authorized by all necessary
corporate  action  and no further  corporate  action or  approval  is or will be
required  for  their  respective  execution,   delivery  and  performance.  This
Agreement  constitutes,  and the  Subscription  Agreements  and Placement  Agent
Option,  upon  execution  and  delivery  will  constitute,   valid  and  binding
obligations  of the Company,  enforceable  in accordance  with their  respective
terms (except (i) as the enforceability  thereof may be limited by bankruptcy or
other laws now or hereafter in effect relating to or affecting creditors' rights
generally, (ii) that the remedy of specific performance and injunctive and other
forms of  equitable  relief  may be  subject to  equitable  defenses  and to the
discretion  of the court before which any  proceedings  therefor may be brought,
and  (iii)  that the  enforceability  of the  indemnification  and  contribution
provisions of the respective  agreements may be limited by the federal and state
securities laws and public  policy),  and no consent,  approval,  authorization,
order of, or filing with, any court or governmental authority or any other third
party is required to consummate the transactions contemplated by this Agreement,
the Subscription Agreements or Placement Agent Option, except that the offer and
sale of the  Preferred  Stock in  certain  jurisdictions  may be  subject to the
provisions  of  the   securities  or  Blue  Sky  laws  of  such   jurisdictions.
Additionally, other than such consents as may have already been



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obtained, no consent, approval, authorization,  order of, filing with, any court
or governmental authority or any other third party is required to consummate the
transactions contemplated by this Agreement, the Subscription Agreements and the
Placement Agent Option.

     (g)  Non-Contravention.  The  Company's  execution  and  delivery  of  this
Agreement,  the Subscription  Agreements and the Placement Agent Option, and the
incurring of the obligations  herein and therein set forth, and the consummation
of the transactions contemplated herein and therein, will not (i) conflict with,
or constitute a breach of, or a default under,  the Certificate of Incorporation
or  By-Laws  of the  Company,  or any  contract,  lease  or other  agreement  or
instrument  to  which  the  Company  is a party or in which  the  Company  has a
beneficial  interest  or by which  the  Company  is  bound,  except  where  such
breach(es) or default(s),  singly or in the aggregate, would not have a material
adverse effect on the Company;  (ii) violate any existing  applicable law, rule,
regulation,  judgment,  order or  decree  of any  governmental  agency or court,
domestic  or  foreign,  having  jurisdiction  over  the  Company  or  any of its
properties  or  business,  except  where  such  violation(s),  singly  or in the
aggregate,  would not have a material  adverse  effect on the Company;  or (iii)
have any material  adverse  effect on any approval  necessary for the Company to
own, lease or operate any of its properties or to conduct its business.

     (h) Valid  Issuances.  The  Preferred  Stock,  when issued and delivered in
accordance  with the terms of the Offering  Documents,  will be duly and validly
issued,  fully paid and  non-assessable.  The Placement Agent Option when issued
and  delivered in accordance  with the terms of this  Agreement or the Placement
Agent Option,  as the case may be, will be duly and validly  issued.  The Common
Stock  issuable  upon  conversion  of the  Preferred  Stock and  exercise of the
Placement Agent Option when issued and delivered in accordance with their terms,
will be duly and validly issued, fully paid and non-assessable.  The Company has
reserved for issuance a sufficient number of shares of Common Stock to be issued
upon  conversion  of the  Preferred  Stock and exercise of the  Placement  Agent
Option.

     (i)  Offering  Documents;  10b-5  Representation.  The  Offering  Documents
conform in all material  respects with the  requirements  of Section 4(2) and/or
3(b) of the Securities Act and Rules 501-506 of Reg D and with the  requirements
of all other  applicable  rules and  regulations  of the Securities and Exchange
Commission  (the   "Commission")   currently  in  effect  relating  to  "private
offerings." The Offering Documents, taken as a whole, do not con tain any untrue
statement of a material  fact or omit to state any 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.

     (j)  Exchange  Act  Reports.  The  Company  is  subject  to  the  reporting
requirements  of the  Securities  Act and  Securities  Exchange Act of 1934,  as
amended ("Exchange Act") and has filed all reports and statements required under
the  Securities  Act and  Exchange  Act on a timely  basis,  and each report and
statement was true and complete in all material respects when filed.

     (k)  Subsidiaries.  Whenever  the context of this  Agreement  permits,  the
representations  and warranties made by the Company in this Agreement shall also
apply and be true with  respect to each  subsidiary  individually  and as to the
Company taken as a whole with all the  subsidiaries,  as if each  representation
and warranty  contained  herein made specific  reference to the subsidiary  each
time the term "Company" is used.




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     8.  Representations  and Warranties of the Placement  Agent.  The Placement
Agent represents and warrants as follows:

     (a) Due Incorporation. The Placement Agent is duly incorporated and validly
existing and in good standing under the laws of its state of  incorporation  and
is duly qualified as a foreign  corporation  for the transaction of business and
is in good  standing in each  jurisdiction  where the failure to be so qualified
would not have a  materially  adverse  effect on the  business of the  Placement
Agent.

     (b)  Broker-Dealer  Registration.  The  Placement  Agent is registered as a
broker-dealer under Section 15 of the Exchange Act.

     (c) Good Standing.  The Placement Agent is a member in good standing of the
NASD.

     (d)  Sales  in  Certain  Jurisdictions.  Sales  of  Preferred  Stock by the
Placement Agent will be made only in such  jurisdictions  in which the Placement
Agent is a registered  broker-dealer or where an applicable  exemption from such
registration exists.

     (e)  Compliance  with  Laws.  Offers  and sales of  Preferred  Stock by the
Placement Agent will be made in compliance with the provisions of Rule 502(c) of
Reg D of the  Securities  Act,  and the  Placement  Agent  will  furnish to each
investor a copy of the Offering  Documents  prior to accepting  any payments for
the Preferred  Stock. The Placement Agent will offer the Preferred Stock only in
the jurisdictions  indicated in the Blue Sky Survey delivered by Graubard Mollen
& Miller ("GM&M") and in accordance with the limitations set forth therein.

     (f)  Disqualification  Provisions.  Neither  the  Placement  Agent  nor any
principal,  director,  officer  or  agent  thereof  is  subject  to  any  of the
disqualification  provisions  set  forth  in  Rules  262(b)  or  (c)  under  the
Securities Act or state law applicable to the transactions contemplated hereby.

     9. Closings.

     (a) Closings.  The Closings will take place at the offices of GM&M, located
at 600 Third Avenue,  New York,  New York.  At each  Closing,  the Company shall
deliver to the  Subscribers for the shares of Preferred Stock being purchased at
such Closing,  certificates  representing  the Preferred  Stock against  payment
therefor by wire transfer.

     (b) Deliveries at each Closing. At each Closing, and as a condition to each
Closing,  the Company  shall  deliver or cause to be delivered to the  Placement
Agent on behalf of the Placement Agent and the Subscribers:

     a.  Officers'  Certificate.  A  certificate  of the  Company,  signed by an
executive  officer thereof stating that (a) the  representations  and warranties
contained in Section 2 hereof are true and accurate in all material  respects at
each Closing,  with the same effect as though expressly made at each Closing and
(b) that all covenants  and  agreements to be complied with by the Company prior
to the Closing have been complied with;

     b.  Secretary's  Certificate.  A certificate of the Company,  signed by the
Secretary or Assistant  Secretary thereof,  certifying that the attached copy of
the Certificate of


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Incorporation,  as amended by the  Certificate  of  Designations  related to the
Preferred Stock, is in full force and effect, and has not been amended.

     c. Certificates.  The certificates  representing the Preferred Stock in the
names  of  the   Subscribers   at  such  Closing  and,  at  the  last   Closing,
notwithstanding  the preamble to this Section 4.2, the Placement Agent Option in
such names as it designates.

     d. Other  Documents.  Such other  Closing  documents as shall be reasonably
requested by the Placement Agent.

     (c) Placement Agent's Fees and Expenses. At each Closing, the Company shall
pay to the Placement Agent a commission  equal to 10% of the aggregate  purchase
price of the Preferred Stock sold. On or before the Initial Closing, the Company
shall pay the legal fees and  disbursements of GM&M referred to in paragraph 5.2
below.  All the  foregoing  amounts are payable  directly to the parties who are
owed same by deduction from the aggregate pur chase price of the Preferred Stock
sold.

     (d) Issuance of Placement Agent Option. At the last Closing with respect to
the Offering,  the Company shall issue to the Placement  Agent or its designees,
five-year  options  ("Placement Agent Option") to purchase that number of shares
of Common Stock  equivalent to one share of Common Stock for every two shares of
Preferred  Stock sold to  subscribers  in the Offering,  at a purchase  price of
$3.00 per share of Common Stock, exercisable until the fifth anniversary date of
the Initial  Closing.  The  Placement  Agent Option shall  contain  registration
rights  with  respect  to the  shares  underlying  the  Placement  Agent  Option
identical to the registration rights granted to the Subscribers in the Offering.

     (e) GKN Securities Corp. Letter. At the first Closing,  with respect to the
Offering,  the Company will deliver to the Placement  Agent a letter pursuant to
which GKN Securities  Corp.  will waive its right of first refusal in respect of
the Offering and agreeing not to release certain officers and directors from the
lockup agreements given in connection with offering of securities by the Company
on April 3, 1996.

     10. Covenants. The Company covenants and agrees that:

     (a) Amendments to Offering Documents. Until the Offering has been completed
or terminated,  if there shall occur any event  relating to or affecting,  among
other things,  the Company or any affiliate,  or the proposed  operations of the
Company taken as a whole as described in the Offering Documents,  as a result of
which it is  necessary,  in the opinion of counsel for the Company,  to amend or
supplement the Offering  Documents in order that the Offering Documents will not
contain an untrue  statement of a material fact or omit to state a material fact
necessary  in  order  to  make  the  statements  therein,  in the  light  of the
circumstances  under which they were made,  not  misleading,  the Company  shall
immediately  prepare and furnish to the Placement  Agent a reasonable  number of
copies of an appropriate  amendment of or supplement to the Offering  Documents,
in form and substance satisfactory to the Placement Agent.

     (b) Expenses of Offering.  The Company shall be responsible  for, and shall
pay,  all fees,  disbursements  and  expenses  incurred in  connection  with the
Offering, including, but not limited to, the Company's legal (including the fees
and disbursements of GM&M) and accounting fees and  disbursements,  the costs of
preparing,  mailing and  delivering  the Offering  Documents and  amendments and
supplements thereto, this Agreement, the Subscription



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Agreements  and the Placement  Agent Option and related  documents  (all in such
quantities  as the  Placement  Agent  may  reasonably  require),  preparing  and
printing   stock,   filing  fees,   costs  and  expenses   (including  fees  and
disbursements  of GM&M) incurred in qualifying the Offering under the "Blue Sky"
laws of the states  reasonably  specified  by the  Placement  Agent (which fees,
excluding disbursements, shall be $5,000).

     (c)  Further  Assurances.  The  Company  will take such  actions  as may be
reasonably  required or desirable to carry out the  provisions of this Agreement
and the transactions contemplated hereby.

     (d) Accuracy of Representations  and Warranties.  The Company hereby agrees
that,  prior to the Termination  Date, it will take no action,  and use its best
efforts to prevent the occurrence of any event, which could result in any of its
representations,  warranties or covenants  contained in this Agreement or any of
the Offering  Documents  not to be true and  correct,  or not to be performed as
contemplated,  at and as of the time  immediately  after the  occurrence of such
transaction or event.

     11. Registration Rights; Subscriber Lockup.

     (a) Registration Rights. As additional consideration for this Agreement and
the  transactions  contemplated  hereby,  the Company  agrees with the Placement
Agent and will agree with each  Subscriber,  as the case may be, to register for
resale under a Registration Statement ("Registration Statement") pursuant to the
Securities Act and the Blue Sky or state  securities  laws of states  reasonably
selected by the Placement Agent, the Common Stock into which the Preferred Stock
is convertible and the Common Stock  underlying the Placement Agent Option.  The
Company  agrees that the  Registration  Statement will be filed on or before the
one-month anniversary of the Initial Closing. The Company agrees to use its best
efforts to have the Registration  Statement  declared  effective by February 14,
1997. If the  Registration  Statement is not declared  effective by the close of
business on April 15, 1997, as provided in the Certificate of  Designations  for
the Preferred Stock, the conversion rate will be lowered. The Company shall keep
the  Registration  Statement  effective  and  current  until all the  securities
registered  thereunder  are  sold or the  securities  may be sold by the  holder
pursuant to Rule 144, subject to customary "blackout" periods referred to in the
Placement Agent Option and the  Subscription  Agreement.  The Company shall bear
all the  expenses  and  pay  all the  fees it  incurs  in  connection  with  the
preparation, filing and modification or amendment of the Registration Statement.

     12. Indemnification and Contribution.

     (a)  Indemnification  by the Company.  The Company  agrees to indemnify and
hold  harmless the  Placement  Agent and each  person,  if any, who controls the
Placement Agent within the meaning of the Securities Act and/or the Exchange Act
against any losses, claims,  damages or liabilities,  joint or several, to which
the Placement Agent or such  controlling  person may become  subject,  under the
Securities  Act or  otherwise,  insofar  as  such  losses,  claims,  damages  or
liabilities  (or actions in respect  thereof) arise out of or are based upon (i)
any untrue  statement or alleged  untrue  statement of a material fact contained
(A) in the  Offering  Documents,  or (B) in any  blue sky  application  or other
document  executed by the Company  specifically  for blue sky  purposes or based
upon any other written information  furnished by the Company or on its behalf to
any state or other  jurisdiction in order to qualify any or all of the Preferred
Stock under the  securities  laws  thereof  (any such  application,  document or
information  being  hereinafter  called  a "Blue  Sky  Application");  (ii)  the
omission or alleged  omission by the Company to state in the Offering  Documents
or in any Blue Sky Application a material fact required to be



                                        7





stated  therein or necessary  to make the  statements  therein,  in light of the
circumstances under which they were made, not misleading; or (iii) any breach by
the Company of any of its  representations,  warranties  or covenants  contained
herein or in the  Subscription  Agreements  or  Placement  Agent Option and will
reimburse the Placement Agent and each such controlling  person for any legal or
other expenses  reasonably  incurred by the Placement Agent or such  controlling
person in  connection  with  investigating  or defending  any such loss,  claim,
damage,  liability or action;  provided,  however,  that the Company will not be
liable in any such  case to the  extent  that any such  loss,  claim,  damage or
liability  arises  out of or is based  solely  upon (a) an untrue  statement  or
alleged untrue  statement or omission or alleged  omission made in reliance upon
and in conformity with written  information  regarding the Placement Agent which
is furnished to the Company by the Placement Agent specifically for inclusion in
the Offering  Documents or any such Blue Sky  Application;  or (b) any breach by
the Placement Agent of its  representations,  warranties or covenants  contained
herein  (collectively,  (a) and (b) above are referred to as the  "Non-Indemnity
Events").

     (b)  Indemnification  by the Placement Agent. The Placement Agent agrees to
indemnify  and hold  harmless the Company and each person,  if any, who controls
the Company  within the meaning of the  Securities  Act and/or the  Exchange Act
against any losses, claims,  damages or liabilities,  joint or several, to which
the Company or such controlling person may become subject,  under the Securities
Act or otherwise  insofar as such losses,  claims,  damages or  liabilities  (or
actions in  respect  thereof)  arise out of or are based upon any  Non-Indemnity
Event; and will reimburse the Company for any legal or other expenses reasonably
incurred by the Company in connection with  investigating  or defending any such
loss, claim, damage,  liability or action provided that such loss, claim, damage
or  liability  is  found  ultimately  to  arise  out  of or be  based  upon  any
Non-Indemnity Event.

     (c) Procedure.  Promptly  after receipt by an indemnified  party under this
Section 7 of notice of the commencement of any action,  such  indemnified  party
will, if a claim in respect thereof is to be made against any indemnifying party
under  this  Section  7,  notify  in  writing  the  indemnifying  party  of  the
commencement  thereof; and the omission so to notify the indemnifying party will
relieve the indemnifying party from any liability under this Section 7 as to the
particular item for which  indemnification is then being sought (if such failure
materially  prejudices the indemnifying party), but not from any other liability
which it may have to any  indemnified  party. In case any such action is brought
against any  indemnified  party,  and it notifies an  indemnifying  party of the
commencement  thereof,  the  indemnifying  party will be entitled to participate
therein, and to the extent that it may wish, jointly with any other indemnifying
party, similarly notified, to assume the defense thereof, with counsel who shall
be to the reasonable  satisfaction of such  indemnified  party, and after notice
from the  indemnifying  party to such  indemnified  party of its  election so to
assume the defense thereof,  the  indemnifying  party will not be liable to such
indemnified  party  under  this  Section  7 for  any  legal  or  other  expenses
subsequently  incurred by such indemnified  party in connection with the defense
thereof other than  reasonable  costs of  investigation.  Any such  indemnifying
party  shall not be  liable  to any such  indemnified  party on  account  of any
settlement  of any  claim  or  action  effected  without  the  consent  of  such
indemnifying party, which consent shall not be unreasonably withheld.

     (d) Contribution.  If the indemnification provided for in this Section 7 is
unavailable to any indemnified party in respect to any losses, claims,  damages,
liabilities or expenses  referred to therein,  then the  indemnifying  party, in
lieu of indemnifying such indemnified  party, will contribute to the amount paid
or  payable  by such  indemnified  party,  as a result of such  losses,  claims,
damages,  liabilities  or expenses (i) in such  proportion as is  appropriate to
reflect the relative benefits received by the Company on the one hand, and the



                                        8





Placement Agent on the other hand, from the Offering,  or (ii) if the allocation
provided  by clause  (i)  above is not  permitted  by  applicable  law,  in such
proportion as is appropriate to reflect not only the relative  benefits referred
to in clause (i) above,  but also the  relative  fault of the Company on the one
hand,  and of the  Placement  Agent on the other hand,  in  connection  with the
statements  or  omissions  which  resulted  in  such  losses,  claims,  damages,
liabilities or expenses as well as any other relevant equitable  considerations.
The relative benefits received by the Company on the one hand, and the Placement
Agent on the other  hand,  shall be deemed to be in the same  proportion  as the
total proceeds from the Offering (net of sales commissions, but before deducting
other expenses) received by the Company, bear to the commissions received by the
Placement  Agent.  The  relative  fault of the Company on the one hand,  and the
Placement  Agent on the other hand,  will be determined with reference to, among
other things,  whether the untrue or alleged untrue statement of a material fact
or the omission to state a material fact relates to information  supplied by the
Company,  and  its  relative  intent,  knowledge,   access  to  information  and
opportunity to correct or prevent such statement or omission.

     (e) Equitable  Considerations.  The Company and the  Placement  Agent agree
that it would not be just and equitable if contribution pursuant to this Section
7 were  determined  by pro rata  allocation or by any other method of allocation
which does not take into account the equitable considerations referred to in the
immediately preceding paragraph.

     (f) Attorneys'  Fees. The amount payable by a party under this Section 7 as
a result of the losses,  claims,  damages,  liabilities or expenses  referred to
above will be deemed to include any legal or other fees or  expenses  reasonably
incurred by such party in connection with  investigating or defending any action
or claim  (including,  without  limitation,  fees and  disbursements  of counsel
incurred  by an  indemnified  party in any  action  or  proceeding  between  the
indemnifying  party and indemnified  party or between the indemnified  party and
any third party or otherwise).

     13.  Termination of Agreement.  The Placement  Agent will have the right to
terminate this Agreement by giving written notice, as herein  specified,  at any
time,  at or prior to the  Closing  if: (i)  material  information  comes to the
attention of the Placement Agent relating to the Company,  its management or its
position in the  industry  which would  preclude a successful  Offering;  (ii) a
material  adverse  change has occurred in the financial  condition,  business or
prospects of the Company (it being  understood that losses not  significantly in
excess of losses for prior  periods  shall not be deemed to be material  adverse
changes); or (iii) the Company has breached any of its material representations,
warranties or obligations hereunder, or failed to expeditiously proceed with the
Offering.  Notwithstanding  anything  contained  herein  to the  contrary,  if a
Closing does not occur by December  15,  1996,  through no fault of the Company,
the Company may terminate this Agreement. The provisions of Sections 7, 8 and 18
of this  Agreement  shall  survive the  termination  of this  Agreement  for any
reason.

     14.  Notices.  Any  notice  hereunder  shall  be in  writing  and  shall be
effective  when delivered in person or by facsimile  transmission,  or mailed by
certified mail, postage prepaid,  return receipt  requested,  to the appropriate
party or parties,  at the following  addresses:  if to the Placement  Agent,  to
Perrin,  Holden & Davenport Capital Corp., 17 John Street,  3rd Floor, New York,
New York 10038, Attention: Jody Eisenman,  President (Fax No. 212/566-4977);  if
to the Company, to H.E.R.C. Products Incorporated,  2202 West Lone Cactus Drive,
#15,  Phoenix,  Arizona 85027,  Attention:  Gary S. Glatter,  President (Fax No.
602/233-1107);  and, in either  case,  a copy to Graubard  Mollen & Miller,  600
Third Avenue, New York, New York 10016, Attention:  David Alan Miller, Esq. (Fax
No.  212/687-6989);  or, in each case,  to such other address as the parties may
hereinafter designated by like notice.



                                        9





     15.  Parties.  This  Agreement  will inure to the benefit of and be binding
upon the parties hereto and their  respective  successors  and assigns.  Neither
party may assign this Agreement or its obligations  hereunder  without the prior
written consent of the other party. This Agreement is intended to be, and is for
the sole and exclusive  benefit of the parties hereto and the persons  described
in Section 7.1 and 7.2 hereof, and their respective  successors and assigns, and
for the benefit of no other  person,  and no other person will have any legal or
equitable right, remedy or claim under, or in respect of this Agreement.

     16. Amendment and/or Modification.  Neither this Agreement, nor any term or
provision  hereof,  may be changed,  waived,  discharged,  amended,  modified or
terminated  orally,  or in any  manner  other than by an  instrument  in writing
signed by each of the parties hereto.

     17. Further  Assurances.  Each party to this Agreement will perform any and
all acts and execute any and all  documents as may be necessary and proper under
the  circumstances  in order to  accomplish  the  intents  and  purposes of this
Agreement and to carry out its provisions.

     18.  Validity.  In case any term of this  Agreement  will be held  invalid,
illegal or unenforceable,  in whole or in part, the validity of any of the other
terms of this Agreement will not in any way be affected thereby.

     19. Waiver of Breach. The failure of any party hereto to insist upon strict
performance  of any of the  covenants and  agreements  herein  contained,  or to
exercise any option or right herein conferred in any one or more instances, will
not be construed to be a waiver or  relinquishment  of any such option or right,
or of any other covenants or agreements, and the same will be and remain in full
force and effect.

     20. Entire  Agreement.  This  Agreement  contains the entire  agreement and
understanding  of the  parties  with  respect to the subject  matter  hereof and
thereof, respectively, and there are no representations,  inducements,  promises
or agreements,  oral or otherwise,  not embodied in this Agreement.  Any and all
prior discussions,  negotiations,  commitments and understanding relating to the
subject matter of these agreements are superseded by them.

     21.  Counterparts.  This Agreement may be executed in counterparts and each
of such counterparts will for all purposes be deemed to be an original, and such
counterparts will together constitute one and the same instrument.

     22. Law. This  Agreement  will be deemed to have been made and delivered in
New York City and will be governed as to validity, interpretation, construction,
effect and in all other  respects by the internal laws of the State of New York.
The Company (i) agrees that any legal suit, action or proceeding  arising out of
or relating to this Agreement shall be instituted  exclusively in New York State
Supreme  Court,  County of New York, or in the United States  District Court for
the Southern District of New York, (ii) waives any objection to the venue of any
such  suit,  action  or  proceeding,  and  (iii)  irrevocably  consents  to  the
jurisdiction  of the New York State Supreme  Court,  County of New York, and the
United States  District Court for the Southern  District of New York in any such
suit, action or proceeding. The Company further agrees to accept and acknowledge
service of any and all process  which may be served in any such suit,  action or
proceeding  brought in the New York State Supreme Court,  County of New York, or
in the United States  District  Court for the Southern  District of New York and
agrees that service of process  upon it mailed by certified  mail to its address
shall be deemed in every  respect  effective  service of process  upon it in any
suit, action or proceeding.




                                       10





     23.  Representations,  Warranties  and Covenants to Survive  Delivery.  The
respective representations,  indemnities,  agreements, covenants, warranties and
other statements of the Company and the Placement Agent shall survive  execution
of this Agreement and delivery of the Preferred  Stock and/or the termination of
this Agreement prior thereto.

         If you find the  foregoing  is in  accordance  with our  understanding,
kindly sign and return to us a counterpart  hereof,  whereupon  this  instrument
along with all counterparts will become a binding agreement between us.

                                                Very truly yours,

                                                H.E.R.C. PRODUCTS INCORPORATED


                                                  /s/ Gary S. Glatter
                                                -------------------------------
                                                Gary S. Glatter, President

AGREED:

PERRIN, HOLDEN & DAVENPORT
  CAPITAL CORP.


By:      /s/ Jody Eisenman
   ---------------------------
      Jody Eisenman, President



                                       11





                         H.E.R.C. PRODUCTS INCORPORATED
                           2202 WEST LONE CACTUS DRIVE
                                    SUITE 15
                             PHOENIX, ARIZONA 85027



                                                              December 5, 1996



Perrin, Holden & Davenport Capital Corp.
17 John Street, 3rd Floor
New York, New York 10038

   Re:    Private Offering of Preferred Stock of H.E.R.C. Products Incorporated

Gentlemen:

                  Reference  is  made  to  the  Agency  Agreement,  dated  as of
November 15, 1996, between you and H.E.R.C.  Products Incorporated  ("Company"),
pursuant to which the Company proposed to offer for sale in a private  placement
("Offering"),  up to  $1,500,000  in  aggregate  purchase  price  of  shares  of
preferred stock, $.01 par value ("Preferred Stock") on a "best efforts,  minimum
$1,000,000,  maximum  $1,500,000  basis."  This is to confirm our  agreement  to
increase the Offering to up to $1,850,000 in aggregate  purchase price of shares
of Preferred Stock on a "best efforts,  minimum  $1,000,000,  maximum $1,850,000
basis."

                  If  you  find  the  foregoing  is  in   accordance   with  our
understanding, please execute a copy of this letter where indicated below.

                                                Sincerely,

                                                H.E.R.C. PRODUCTS INCORPORATED


                                                By:      /s/ Gary S. Glatter
                                                   ---------------------------
                                                    Gary S. Glatter, President

AGREED:

PERRIN, HOLDEN & DAVENPORT CAPITAL CORP.


By:      /s/ Jody Eisenman
   -----------------------------
      Jody Eisenman, President



                                       12