THIRD AMENDMENT TO PROMISSORY NOTE

     THIS THIRD AMENDMENT TO PROMISSORY NOTE ("Amendment") is made as of October
16, 2000 between OPEC CORPORATION, a Colorado corporation (the "Borrower"),  and
U.S. BANK NATIONAL ASSOCIATION, a national banking association (the "Lender").

                                   RECITALS:

     A. The Lender made a loan to the Borrower,  which loan is evidenced by that
certain Promissory Note dated August 3, 1998 made by the Borrower payable to the
Lender in the original principal amount of $480,000, as amended by that certain
Change  In Terms  Agreement  dated  August  25,  1999 and  that  certain  Second
Amendment to Promissory Note dated as of April 17, 2000 (as so amended, the "L/C
Note").

     B. The Lender made a loan to the Borrower,  which loan is evidenced by that
certain Combination  Promissory Note and Loan Agreement dated April 7, 1998 made
by the Borrower  payable to Lender in the original  principal  amount of $20,000
(the "Term Note" and collectively with the L/C Note, the "Notes").

     C. The Borrower and the Lender have entered into that certain Business Loan
Agreement dated August 3, 1998 (the "Loan Agreement").

     D. The  Borrower's  obligations  under the Notes and the Loan Agreement are
secured  by,  INTER  ALIA,  a security  interest  in the  Borrower's  inventory,
equipment,  accounts,  instruments,  chattel paper,  other rights to payment and
general  intangibles  pursuant to those certain Borrower's  Security  Agreements
dated December 24, 1997 and April 7, 1998 and that certain  Commercial  Security
Agreement  dated  August 3, 1998,  from the  Borrower  to Lender  (the,"Security
Agreements") and that security interest has been properly perfected.  The Notes,
the Loan Agreement, the Security Agreements,  and all other instruments executed
by the Borrower in connection therewith are collectively the "Credit Documents."

     E. The  Borrower's  obligations  under the Notes and the Loan Agreement are
absolutely and unconditionally guarantied by: (i) those certain Guaranties dated
December 24, 1997,  April 7, 1998 and August 3, 1998 made by Donald D.  Cannella
("Cannella")  in favor of the Lender;  and (ii) those certain  Guaranties  dated
December  24,  1997,  April 7, 1998 and August 3, 1998 made by Daniel J.  Romano
("Romano") in favor of the Lender (Cannella,  and Romano are, collectively,  the
"Guarantors").

     F. All amounts of  principal  and interest  outstanding  under the L/C Note
were due and payable in full on September  15,  2000.  The Borrower has not paid
the amounts  outstanding under the L/C Note and the failure to do so constitutes
an "Event of Default" under the Loan Agreement and the Notes.
<PAGE>
     G. The Borrower has requested  that the Lender extend the maturity date of
the L/C Note and the Lender is willing to do so if and only if:

          (i)  the Borrower and the Lender enter into this Amendment;

          (ii) the Borrower causes each of the Guarantors to execute and deliver
               to the  Lender  a  consent  to  This  Amendment  (the  "Guarantor
               Consents"),  each  dated  as of the date  hereof  and in form and
               substance  satisfactory to the Lender;  and the Borrower complies
               with  the  other  conditions  contained  in the  Notes,  the Loan
               Agreement and this Amendment.

                                   AGREEMENT:

     NOW, THEREFORE,  in consideration of the foregoing recitals, the agreements
set forth  herein and other good and  valuable  consideration,  the  receipt and
sufficiency of which are hereby  acknowledged,  the parties hereby  covenant and
agree as follows:

     1.   INCORPORATION   OF  RECITALS.   The  foregoing   recitals  are  hereby
incorporated herein and made a part hereof.

     2.  CONFIRMATION OF INDEBTEDNESS.  The outstanding  principal balance under
the L/C Note as of October 11, 2000 is $430,000.00.  The  outstanding  principal
balance under the Term Note as of October 11, 2000 is $$4,385.33.

     3. AMENDMENT TO L/C NOTE. The terms of the L/C Note are changed as follows:

          (a)  The  caption in the L/C Note  entitled  "MATURITY  9-15-2000"  is
               deleted and replaced with "MATURITY 12-31-2000."

          (b)  The  caption in the L/C Note  entitled  "PRINCIPAL  $480,000"  is
               deleted and replaced with "PRINCIPAL $430,000."

          (c)  The  caption  near  the top of the L/C  Note  READING  "PRINCIPAL
               AMOUNT:  $480,000.00"  is deleted and  replaced  with  "PRINCIPAL
               AMOUNT: $430,000."

          (d)  The first sentence of the paragraph captioned "PROMISE TO PAY" is
               deleted in its entirety and replaced  with the  following:  "OPEC
               CORPORATION  ("BORROWER")  PROMISES TO PAY TO U.S.  BANK NATIONAL
               ASSOCIATION  ("LEADER"),  OR ORDER, IN LAWFUL MONEY OF THE UNITED
               STATES OF AMERICA,  THE PRINCIPAL  AMOUNT OF FOUR HUNDRED  THIRTY
               THOUSAND 00/100 ($430,000.00) OR SO MUCH AS MAY

                                        2
<PAGE>
               be outstanding,  together with interest on THE UNPAID OUTSTANDING
               PRINCIPAL BALANCE of each advance."

          (e)  The  first  sentence  of the  paragraph  captioned  "PAYMENT"  is
               deleted  in  its  entirety  and  replaced  with  the   following:
               "Borrower  will pay this loan IN ONE  PAYMENT OF ALL  OUTSTANDING
               PRINCIPAL PLUS ALL ACCRUED UNPAID INTEREST ON DECEMBER 31, 2000."

     4. CONDITIONS TO  EFFECTIVENESS  OF AMENDMENT.  This Amendment shall become
effective as of the date first above written when the Lender shall have received
and, as  applicable,  executed  each of the  following:  (i) an original of this
Amendment,  duly executed by the Borrower; (ii) the original Guarantor Consents,
duly executed by each Guarantor, in form and content satisfactory to the Lender;
and (iii)  such  additional  information  or  documentation  as the  Lender  may
require.  If the Lender has not received  all of the  foregoing on or before the
date first above  written,  then the Lender's  offer to make the  agreements set
forth herein may be terminated, at the Lender's option, by giving notice to the
Borrower.

     5. GENERAL RELEASE. The Borrower, for and on behalf of itself and its legal
representatives,  heirs,  successors  and assigns,  does hereby waive,  release,
relinquish and forever discharge the Lender and its past and present  directors,
officers,  agents,  employees,  parents,  subsidiaries,   affiliates,  insurers,
attorneys,  representatives and assigns, and each and all thereof (collectively,
the "Released  Parties"),  of and from any and all manner of action or causes of
action, suits, claims, demands, judgments, damages, levies, and the execution of
whatsoever kind, nature and/or  description  arising on or before the date first
above written,  including,  without  limitation,  any claims,  losses,  costs or
damages, including compensatory and punitive damages, in each case whether known
or unknown, liquidated or unliquidated, fixed or contingent, direct or indirect,
which the Borrower, or its legal representatives,  heirs, successors or assigns,
ever had or now has or may claim to have against any of the  Released  Parties,
with respect to any matter whatsoever arising on or before said date.

     6. EFFECT OF AMENDMENT;  REPRESENTATIONS AND WARRANTIES. The Lender and the
Borrower agree that after this  Amendment  becomes  effective,  the L/C Note, as
hereby amended, shall remain in full force and effect. The Borrower warrants and
represents  that on and as of the date  hereof and after  giving  effect to this
Amendment,  there  will  exist no  event  of  default  under  any of the  Credit
Documents,  or circumstances that with the giving of notice, the passage of time
or both will constitute an event of default under any of the Credit Documents on
such date. The Borrower  represents and warrants that it has the power and legal
eight  and  authority  to enter  into  this  Amendment,  and that  neither  this
Amendment,  nor the  agreements  contained  herein,  contravene  or constitute a
default under any agreement,  instrument or indenture to which the Borrower is a
party or signatory or any provision of the Borrower's articles of incorporation,
bylaws,  or, to the best of the  Borrower's  knowledge,  any other  agreement or
requirement  of law.  The  Borrower  represents  and  warrants  that no consent,
approval or authorization of or

                                        3
<PAGE>
registration  or declaration  with any party,  including belt not limited to any
governmental  authority,  is  required  in  connection  with the  execution  and
delivery  by  the  Borrower  of  this  Amendment,  or  the  performance  of  the
obligations of the Borrower herein described.

     7.  RATIFICATION OF CREDIT  DOCUMENTS.  Except as expressly  modified under
this  Amendment,   all  of  the  terms,  conditions,   provisions,   agreements,
requirements,  promises,  obligations,  duties, covenants and representations of
the Borrower  under the Credit  Documents  and any and all other  documents  and
agreements  entered into with respect to the  Borrower's  obligations  under the
Credit  Documents are  incorporated  herein by reference and are hereby ratified
and affirmed in all respects by the Borrower.  The Borrower further acknowledges
and  agrees  that the  security  interests  created by the  Security  Agreements
continue to secure the obligations of the Borrower under the Term Note, the Loan
Agreement and the L/C Note, as amended by this Agreement.

     8. MERGER AND INTEGRATION,  SUPERSEDING EFFECT. This Amendment embodies the
entire  agreement and  understanding  between the parties hereto with respect to
the subject  matter hereof and  supersedes  and has merged into it ALL PRIOR and
written  agreements in the same subjects by and between the parties  hereto with
the effect that this Amendment shall control.

     9. GOVERNING LAW. THIS  AMENDMENTS IS GOVERNED BY THE LAWS OF THE STATE OF
COLORADO.

     IN WITNESS  WHEREOF,  the parties  hereto have caused this  Amendment to be
executed and delivered as of the date and year first above written.


                                        OPEC CORPORATION, a Colorado corporation


                                        By /s/ Donald D. Cannella, Pres.
                                           -------------------------------------
                                           Donald D. Cannella, President


                                        U.S. BANK NATIONAL ASSOCIATION


                                        By /s/ Michael J. Porcello
                                           -------------------------------------
                                           Michael J. Porcello, Assistant Vice
                                           President

                                        4
<PAGE>
STATE OF COLORADO  )
                   )ss.
COUNTY OF _______  )

     On this day before me, the undersigned  Notary Public  personally  appeared
Donald D. Cannella, the President of Opec Corporation, personally known to me or
proved to me on the basis of satisfactory  evidence to be an authorized  officer
of said  corporation  who executed the Third  Amendment to  Promissory  Note and
acknowledged the Third Amendment to Promissory Note to be the free and voluntary
act and deed of the corporation,  by authority of its Bylaws or by resolution of
its board of directors, for the uses and purposes therein mentioned, and on oath
stated that he is authorized to execute the Third  Amendment to Promissory  Note
and in fact  executed the Third  Amendment to  Promissory  Note on behalf of the
corporation.

     Given under my hand and official seal thin 12th day of October, 2000.

By Claire Jean Cannella                 Residing at 4320 Emerald Dr.
   -------------------------------                  ----------------------------

Notary Public in and for                My commission expires 02/23/2002
the State of Minnesota

                                        5
<PAGE>
                             CONSENT OF GUARANTOR(1)

     Pursuant to those certain Guaranties dated December 24, 1997, April 7, 1993
and  August 3, 1995 (the  "Guaranties"),  the  undersigned  has  unconditionally
guaranteed  the payment in full when due of all of Borrower's  Indebtedness  (as
defined in the Guaranties) to Lender. The undersigned hereby:

          (a) consents to the  execution  and delivery by Borrower and Lender of
     the foregoing Third Amendment to Promissory Note (the "Amendment"), and the
     other documents described therein;

          (b) agrees,  confirms and acknowledges  that his obligations under the
     Guaranties  executed  by him:  (i) are in no way  affected  or  impaired by
     reason  of the  execution  and  delivery  of the  Amendment,  and the other
     documents  described  therein,  (ii)  remain in full force and  effect.  in
     accordance with the terms of such Guaranties,  and (iii) continue to secure
     all  amounts  outstanding  under the L/C Note, as amended by the Amendment,
     and the Term Note;

          (c) acknowledge  that there are no existing  offsets,  defenses and/or
     counterclaims  assertable by the  undersigned  relating to his  obligations
     under the Guaranties;

          (d) agrees,  confirms and  acknowledges  that any  indebtedness of the
     Borrower  to the  undersigned,  if any,  is and at all times  shall  remain
     subordinate  to the  indebtedness  of the  Borrower now or hereafter to the
     Bank; and

          (e) ACKNOWLEDGES THAT: (I) HE HAS READ AND UNDERSTOOD THIS CONSENT AND
     THE AMENDMENT IN THEIR  ENTIRETY PRIOR TO SIGNING AND FULLY AGREES TO EACH,
     ALL AND EVERY PROVISION HEREOF AND THEREOF; AND (II) HE HAS RECEIVED A COPY
     HEREOF.

     The undersigned hereby expressly releases and discharges the Bank, and each
of its officers,  directors,  employees,  agents and attorneys, from any and all
claims,  actions,  and liabilities of any kind or nature that the undersigned or
any one  claiming  through  or under him ever had or may now have,  whether  now
known or  HEREAFTER  discovered,  arising  out of or in any way  relating to the
lending  RELATIONSHIP BETWEEN THE BANK and the undersigned,  the Guaranties,  or
any course of conduct or obligations  prior to the date of this instrument.  The
undersigned acknowledges and agrees that he has received the

----------
(1)  Capitalized terms used in this Consent without definition have the meanings
     given in the foregoing Third Amendment to Promissory Note.

                                        6
<PAGE>
advice of independent counsel selected by him, or the opportunity to obtain such
advice,  before  entering into this instrument and have no; relied upon the Bane
or airy of its officers,  directors,  employees,  agents or attorneys concerning
any aspect of this instrument.

Dated: October 12, 2000


                                        /s/ Donald D. Cannella, Pres.
                                        ----------------------------------------
                                        Donald D. Cannella


STATE OF COLORADO  )
                   )ss.
COUNTY OF _______  )

     On this day before me, the undersigned notary public,  personally  appeared
Donald  D.  Lamella,  personally  known to me or  proved  to me on the  basis of
satisfactory  evidence to be the person that executed the foregoing Consent, and
acknowledged the Consent to be his free and voluntary act and deed, for the uses
and proposes  therein  mentioned,  and on oath stated that he is  authorized  to
execute this Consent and in fact executed this Consent.

     Given under my hand and official seal this 12th day of October, 2000.

By Claire Jean Cannella                 Residing at 4320 Emerald Dr.
   -------------------------------                  ----------------------------

Notary Public in and for                My commission expires 02/23/2002
the State of Colorado

                                        7
<PAGE>
                             CONSENT OF GUARANTOR(1)

     Pursuant to those certain Guaranties dated December 24, 1997, April 7, 1998
and  August 3, 1998 (the  "Guaranties"),  the  undersigned  has  unconditionally
guaranteed  the payment in full when due of all of Borrower's  Indebtedness  (as
defined in the Guaranties) to Lender. The undersigned hereby:

          (a) consents to the  execution  and delivery by Borrower and Lender of
     the foregoing Third Amendment to Promissory Note (the "Amendment"), and the
     other documents described therein;

          (b) agrees,  confirms and acknowledges  that his obligations under the
     Guaranties  executed  by him:  (i) are in no way  affected  or  impaired by
     reason  of the  execution  and  delivery  of the  Amendment,  and the other
     documents  described  therein,  (ii)  remain in full  force  and  effect in
     accordance with the terms of such Guaranties,  and (iii) continue to secure
     all amounts  outstanding  under the L/C Note, as amended by the  Amendment,
     and the Term Note;

          (c) acknowledge  that there are no existing  offsets,  defenses and/or
     counterclaims  assertable by the  undersigned  relating to his  obligations
     under the Guaranties;

          {d} agrees,  confirms and  acknowledges  that any  indebtedness of the
     Borrower  to the  undersigned,  if any,  is and at all times  shall  remain
     subordinate  to the  indebtedness  of the  Borrower now or hereafter to the
     Bank; and

          (e) ACKNOWLEDGES THAT: (I) HE HAS READ AND UNDERSTOOD THIS CONSENT AND
     THE AMENDMENT IN THEIR  ENTIRETY PRIOR TO SIGNING AND FULLY AGREES TO EACH,
     ALL AND EVERY PROVISION HEREOF AND THEREOF; AND (II) HE HAS RECEIVED A COPY
     HEREOF.

     The undersigned hereby expressly releases and discharges the Bank, and each
of its officers,  directors,  employees,  agents and attorneys, from any and all
claims,  actions,  and liabilities of any kind or nature that the undersigned or
any one  claiming  through  or under him ever had or may now have,  whether  now
known or  hereafter  discovered,  arising  out of or in any way  relating to the
lending  RELATIONSHIP BETWEEN THE BANK AND the undersigned,  the Guaranties,  or
any course of conduct or obligations  prior to the date of this instrument.  The
undersigned acknowledges and agrees that he has received the

----------
(1)  Capitalized teens used in this Consent without definition have the meanings
     given 111 the foregoing Third Amendment to Promissory Note.

                                        8
<PAGE>
advice of independent counsel selected by him, or the opportunity to obtain such
advice,  before entering into this instrument and have not relied upon the Bank-
or any of its officers, directors,  employees, agents or attorneys concerning my
aspect of this instrument.

Dated: October 12, 2000


STATE OF COLORADO  )
                   )ss.
COUNTY OF _______  )

     On this day before me, the undersigned notary public,  personally  appeared
Daniel  J.  Romano,  personally  known  to me or  proved  to me on the  basis of
satisfactory  evidence to be the person that executed the foregoing Consent, and
acknowledged the Consent to be his flee and voluntary act and deed, for the uses
and purposes  therein  mentioned,  and on oath stated that he is  authorized  to
execute this Consent and in fact executed this Consent.

     Given under my hand and official seal this 12th day of October, 2000.

By Claire Jean Cannella                 Residing at 4320 Emerald Dr.
   -------------------------------                  ----------------------------

Notary Public in and for                My commission expires 02/23/2002
the State of Colorado