<PAGE>   1
                                                                 EXHIBIT 10.18

                             "THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE
                             NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
                             1933, AS AMENDED, OR THE SECURITIES LAW OF ANY
                             STATE. THE SECURITIES MAY NOT BE SOLD, TRANSFERRED,
                             PLEDGED OR HYPOTHECATED IN THE ABSENCE OF EFFECTIVE
                             REGISTRATION STATEMENTS OR AN OPINION OF COUNSEL
                             ACCEPTABLE TO THIS COMPANY THAT REGISTRATION IS NOT
                             REQUIRED."


                              ROCKFORD CORPORATION

                                   SENIOR NOTE
                              DUE FEBRUARY 3, 1999

                       (RENAMING, AMENDING, AND REPLACING
                   A 10.5% CONVERTIBLE SUBORDINATED DEBENTURE
                              DUE FEBRUARY 3, 1999)

$1,000.00                                                       October 28, 1994

         This is a Senior Note due February 3, 1999 (the "Senior Note"), issued
by Rockford Corporation, an Arizona Corporation (the "Company") pursuant to the
terms of the Convertible Subordinated Debenture Amendment Agreement and
Agreement to Rename as Senior Note of even date herewith between the Company and
the original Holder hereof (the "Agreement"). Terms used and not otherwise
defined shall have the meaning given them in the Agreement.


1.       Payment of Principal and Interest.

         The Company, for value received, promises to pay to Ron Trout or
transferee (the "Holder") the principal amount of $1,000.00 on February 3, 1999
and to pay interest thereon at the rate of ten and one-half percent (10.5%) per
annum. Interest shall accrue from the date hereof and shall be paid quarterly,
on each January 15th, April 15th, July 15th, and October 15th hereafter but
commencing on April 15, 1989, until the principal is fully paid. Interest shall
be paid on the basis of a 360-day year of twelve 30-day months.

2.       Payment Prior to Maturity.

         At any time the Company may, at its option, redeem this Senior Note in
whole or in part by paying all interest accrued but unpaid to the date fixed for
redemption plus a redemption price fixed as follows:
<PAGE>   2
<TABLE>
<CAPTION>
                  REDEMPTION DATE                                      REDEMPTION PRICE
                  ---------------                                      ----------------
<S>                                                                    <C>
                  Before February 2, 1995                              105% of Par
                  February 3, 1995 to February 2, 1996                 104% of Par
                  February 3, 1996 to February 2, 1997                 103% of Par
                  February 3, 1997 to February 2, 1998                 102% of Par
                  February 3, 1998 to February 2, 1999                 101% of par
</TABLE>

Notice of any redemption shall be given not less than thirty (30) days, but not
more than ninety (90) days, before the date fixed for redemption. By the date
fixed for redemption, the Holder shall surrender this Senior Note to the Company
at its principal executive offices in exchange for payment therefor. Upon due
tender of the accrued interest through the redemption date plus the redemption
price by the Company, this Senior Note shall not be deemed to be outstanding for
any purpose subsequent to the close of business on the date fixed for
redemption.

3.       Subordination and Priority.

         The indebtedness evidenced by this Senior Note, including the principal
and accrued interest, is expressly subordinate and subject in right of payment
and upon liquidation to the prior payment in full of all "Senior Debt," whether
now outstanding or hereafter created, incurred, assumed or guaranteed. The term
"Senior Debt" shall mean the principal of, premium, if any, and interest on (a)
indebtedness (other than this Senior Note or any previously subordinated
indebtedness) of the Company pursuant to the Company's present credit
arrangements with Norwest Business Credit, Inc. ("NBCI") and Bank of America
Arizona ("BofA"), or pursuant to any refinancing or renewal of such credit
arrangements, (b) indebtedness of the Company which holders of not less than 50%
in principal amount of the Senior Notes agree, in writing, shall be treated as
Senior Debt, and (c) indebtedness incurred, assumed or guaranteed by the Company
in connection with the acquisition by it of any property or asset, in an amount
up to the cost of such property or asset, unless, in each case, by the terms of
the instrument creating or evidencing the indebtedness it is expressly provided
that such indebtedness is not superior in right of payment to this Senior Note.

         Senior Debt shall exclude, and the indebtedness evidenced by this
Senior Note is expressly senior and entitled to priority in payment and upon
liquidation with respect to, all capital stock of the Company, any indebtedness
issued after the date of this Debenture and convertible into shares of the
Company's Common Stock, and any other indebtedness that is not Senior Debt.
Senior Debt shall exclude, and the indebtedness evidenced by this Senior Note is
expressly of equal priority in payment and upon liquidation with respect to, (1)
indebtedness outstanding on the original issue date of this Senior Note and
convertible into shares of the Company's Common Stock and (2) a $2,000,000
Senior Note of Company issued to Provident Mutual Life Insurance Company of
Philadelphia.

4.       Events of Default.

         An Event of Default shall occur upon the occurrence of any of the
following events:


                                      -2-
<PAGE>   3
         4.1      Default in the payment of interest on this Senior Note when it
becomes due and payable, and continuance of such default for a period of ten
(10) days;

         4.2      Default in the payment of the principal of this Senior Note
when it becomes due and payable;

         4.3      Default by the Company under an acceleration prior to maturity
of, or the failure to pay at maturity, any third party indebtedness of the
Company aggregating not less than $250,000 for a period of thirty (30) days
after the same may become payable (which shall include any grace period but
shall not exceed 30 days);

         4.4      The failure of the Company to comply for a period of not less
than thirty (30) consecutive days with any provision of the affirmative or
negative covenants contained in the Agreement;

         4.5      The failure of the Company to pay final judgments not covered
by insurance or then subject to any appeal aggregating in excess of $250,000 for
thirty (30) days;

         4.6      The entry of a decree or order by a court having jurisdiction
adjudging the Company a bankrupt or insolvent, or approving as properly filed a
petition seeking reorganization, arrangement, adjustment or composition of or in
respect of the Company under the Federal Bankruptcy Act or any other applicable
Federal or State law, or appointing a receiver, liquidator, assignee, trustee,
or other similar official of the Company or of any substantial part of its
property, or ordering the winding up or liquidation of its affairs, and the
continuance of any such decree or order unstayed and in effect for a period of
thirty (30) consecutive days; or

         4.7      The institution by the Company of proceedings to be
adjudicated a bankrupt or insolvent, or the consent by it to the institution of
bankruptcy or insolvency proceedings against it, or the filing by it of a
petition or answer or consent seeking reorganization or relief under Federal or
State law, or the consent by it to the filing of any such petition or to the
appointment of a receiver, liquidator, assignee, trustee or other similar
official of the Company or of any substantial part of its property, or the
making by it of an assignment for the benefit of creditors, or the admission by
it in writing of its inability to pay its debts generally as they become due, or
the taking of corporate action by the Company in furtherance of any such action.

5.       Rights Upon Default; Acceleration of Indebtedness. Upon the occurrence
of an Event of Default:

         5.1      The entire outstanding balance of the Senior Note, including
the entire balance of principal and all accrued interest, shall accelerate and
become immediately due and payable upon written notice to the Company by Holders
of not less than 50% in principal amount of the Senior Notes then outstanding;
and

         5.2      The Company may not pay dividends or make distributions to
holders of any class of its stock, or redeem or repurchase all or any part of
any class of its stock.


                                      -3-
<PAGE>   4
6.       Renaming and Replacement of Debenture.

         This Senior Note is issued, pursuant to the terms of the Agreement, to
rename and amend the terms of a Debenture issued by the Company and held by the
Holder. This Senior Note shall supersede, replace and amend the Debenture which
shall, upon issuance of this Senior Note, have no further force or effect.

7.       Loss or Destruction of Senior Note.

         The Company shall execute and deliver a new Senior Note of like tenor
and date upon receipt by the Company of evidence satisfactory to it of the loss,
theft, destruction or mutilation of this Senior Note and, in the case of loss,
theft or destruction, of an indemnity by the original Holder hereof or in case
of any transfer upon such terms as may be satisfactory to the Company, or, in
the case of mutilation, upon surrender and cancellation of this Senior Note.

8.       Status Under Securities Laws.

         8.1      No Registration. This Senior Note has not been and will not
be, registered under the Securities Act of 1933 (the "1933 Act"), the Arizona
Securities Act (the "Arizona Act") or the securities laws of any other
jurisdiction and must be held indefinitely without any transfer, sale or other
disposition unless subsequently registered under the 1933 Act, the Arizona Act
and the securities laws of any other applicable jurisdiction or, in the opinion
of counsel acceptable to the Company, registration is not required under such
Acts or laws.

         8.2      Legend. There shall be endorsed on this Senior Note a legend
substantially to the following effect:

         "THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
         UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR THE SECURITIES LAW OF
         ANY STATE. THE SECURITIES MAY NOT BE SOLD, TRANSFERRED, PLEDGED OR
         HYPOTHECATED IN THE ABSENCE OF EFFECTIVE REGISTRATION STATEMENTS OR AN
         OPINION OF COUNSEL ACCEPTABLE TO THIS COMPANY THAT REGISTRATION IS NOT
         REQUIRED."

         8.3      Refusal to Transfer. The Company may refuse to effect a
transfer, sale or other disposition of this Senior Note by the Holder or its
successors or assigns otherwise than as expressly permitted by this Senior Note
and the Agreement.

9.       Miscellaneous.

         9.1      Agreement. This Senior Note and the terms of the indebtedness
evidenced hereby are issued and incurred subject to the terms of the Agreement,
the terms and conditions of which shall become binding upon any subsequent
Holder or transferee of this Senior Note.


                                      -4-
<PAGE>   5
         9.2      Governing Law. This Senior Note and all questions relating to
its validity, interpretation, performance and enforcement shall be governed by
and construed in accordance with the laws of the State of Arizona,
notwithstanding any Arizona or other conflict-of-law provisions to the contrary.

         9.3      Binding Nature of Senior Note. This Senior Note shall be
binding upon any successors and assigns of the Company and shall inure to the
benefit of the Holder and its successors and assigns, except that the Holder may
not assign or transfer its rights under this Senior Note otherwise than by gift
or bequest, by operation of law, or as expressly permitted by this Senior Note.

         9.4      Notices. All notices, requests, demands and other
communications required or permitted under this Senior Note shall be in writing
and shall be deemed to have been duly given, made and received when delivered or
five days after they are deposited in the United States mails, first class
postage prepaid, addressed as set forth below:

                  (1)      If to the Company:

                           648 South River Drive
                           Tempe, Arizona 85281
                           Attention:       President

                           with a copy to:

                           Lewis and Roca
                           40 North Central Avenue, #1500
                           Phoenix, Arizona 85004
                           Attention:       Kevin Olson, Esq.

                  (2)      If to the Holder:

                                      Ron Trout
                                      4328 East Contessa
                                      Mesa, Arizona 85201

                  Either party may alter the person, office or address to which
communications or copies are to be sent by giving notice.

10.      Execution Date. The Company has caused this Senior Note to be duly
executed on the date written above.

                                            ROCKFORD CORPORATION


                                            By:  /s/
                                               ---------------------------------
                                                 President


[Corporate Seal)                            Attest:


                                      -5-
<PAGE>   6
                                                 /s/
                                            ------------------------------------
                                            Assistant Secretary


                                       -6-
<PAGE>   7
         "THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
         UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR THE SECURITIES LAW OF
         ANY STATE. THE SECURITIES MAY NOT BE SOLD, TRANSFERRED, PLEDGED OR
         HYPOTHECATED (EXCEPT TO A COMMERCIAL BANK OR OTHER CORPORATION
         AFFILIATED WITH SECURITY PACIFIC BANK ARIZONA) IN THE ABSENCE OF
         EFFECTIVE REGISTRATION STATEMENTS OR AN OPINION OF COUNSEL ACCEPTABLE
         TO THIS COMPANY THAT REGISTRATION IS NOT REQUIRED."


                                     WARRANT

                   TO PURCHASE UP TO 43 SHARES OF COMMON STOCK

             VOID AFTER 5:00 P.M., PHOENIX TIME, ON FEBRUARY 3, 2000


                              ROCKFORD CORPORATION

                           INCORPORATED UNDER THE LAWS
                             OF THE STATE OF ARIZONA

         This certifies that, for value received, Ron Trout or the registered
holder hereof or assigns (the "Warrantholder") is entitled to purchase from
Rockford Corporation, an Arizona corporation (the "Company"), at any time before
5:00 p.m., Phoenix time, on February 3, 2000, at the purchase price per share of
$ 6.50 (the "Warrant Price"), up to the number of shares of Common Stock, no par
value, of the Company set forth above (the "Shares"). The number of Shares
purchasable upon exercise of this Warrant and the Warrant Price per share shall
be subject to adjustment from time to time as set forth below.

         1.       Agreement. This Warrant was originally delivered pursuant to
the terms of the Convertible Subordinated Debenture Amendment Agreement and
Agreement to Rename as Senior Note between the Company and original
Warrantholder (the "Agreement"). In connection with the Agreement the Company
and the original Warrantholder agreed to (1) rename the Company's 10.5%
Convertible Subordinated Debentures due February 3, 1999 as the Company's
"Senior Notes due February 3, 1999" (the "Note") and (2) deliver the original of
this Warrant to purchase the Shares in order to separately evidence the right to
purchase the Shares (previously established in the Debentures) and amend the
terms for purchase of the Shares. This Warrant (i) evidences the right to
purchase the Shares, (ii) is issued under and in accordance with the Agreement,
(iii) is subject to the terms and provisions contained in the Agreement and the
Note, to all of which the Warrantholder by acceptance of this Warrant consents
and (iv) represents and evidences the same right to purchase the Shares
previously embodied in the Debentures (subject only to the changes set forth in
this Warrant or in the Agreement). Capitalized terms used in this Warrant shall
have the meanings ascribed to them in the Note or
<PAGE>   8
Agreement. This Warrant may be exercised at any time after its issuance and
before 5:00 p.m., Phoenix time, on February 3, 2000.

         2.       Detachment from Note. This Warrant is originally issued
together with the Note; however, it may be transferred independently of the Note
at any time, subject to compliance with the transfer restrictions set forth in
the Agreement.

         3.       Expiration. Unless earlier exercised or expired, this Warrants
shall expire at 5:00 p.m. Phoenix time on February 3, 2000.

         4.       Exercise of Warrant.

                  4.1      Exercise. This Warrant may be exercised in whole or
in part by presentation of this Warrant with the Exercise Form on the reverse
side hereof duly executed and simultaneous payment of the Warrant Price (subject
to adjustment) at the principal office of the Company. Payment of such price
shall be made at the option of the Warrantholder in certified funds or by wire
transfer.

                  4.2      Exercise Price and Fractional Shares. This Warrant is
exercisable, at the option of the Warrantholder, to purchase shares of the
Company's Common Stock at the Warrant Price, subject to adjustment as provided
in this Warrant. The Company shall not be required to issue fractional shares of
Common Stock or other capital stock upon exercise of this Warrant and, in lieu
thereof, shall pay a cash adjustment based upon the then current fair market
value of the Common Stock as determined by the Board of Directors as at the last
business day prior to the date of exercise.

                  4.3      Adjustment Based Upon Stock Dividends, Combination of
Shares or Recapitalization. The Warrant Price and the number of Shares shall be
adjusted if the Company shall at any time after the original issuance of this
Warrant (i) pay a stock dividend on its Common Stock, (ii) subdivide its
outstanding shares of Common Stock into a greater number of shares, (iii)
combine its outstanding shares of Common Stock into a smaller number of shares,
(iv) issue by reclassification of its shares of Common Stock any other special
capital stock of the Company, or (v) distribute to all holders of Common Stock
evidences of indebtedness (including indebtedness convertible into Common Stock
or other securities of Company), securities (including common or preferred stock
of Company), or assets (excluding cash dividends) or rights or warrants to
subscribe for Common Stock or other securities of Company (other than those
mentioned above). Upon the occurrence of an event or events requiring adjustment
of the Warrant Price or an adjustment to the number of Shares or other
securities issuable upon exercise of this Warrant, and thereafter, the
Warrantholder upon exercise of this Warrant shall be entitled to receive the
number of shares of Common Stock or other securities of the Company which the
Warrantholder would have owned or have been entitled to receive after the
happening of any of the events described above had this Warrant been exercised
immediately prior to the happening of such event.

                  4.4      Adjustment Based Upon Stock Issuances. The Warrant
Price shall be adjusted if at any time after the original issuance of this
Warrant the Company issues, or issues rights or warrants to subscribe for or
purchase, Common Stock or securities convertible


                                      -2-
<PAGE>   9
into or exchangeable for Common Stock at less than the Warrant Price. Upon the
occurrence of an event or events requiring adjustment of the Warrant Price under
this section the Warrant Price shall be adjusted to be equal to the price of the
new issue, and thereafter the Warrantholder upon exercise of this Warrant shall
be entitled to purchase the Shares, or other securities of the Company which the
Warrantholder is entitled to receive, based upon the new Warrant Price per
share.

                  4.5      Adjustment Based Upon Merger or Consolidation. In
case of any consolidation or merger to which the Company is a party (other than
a merger in which the Company is the surviving entity and which does not result
in any reclassification of or change in the outstanding Common Stock of the
Company), or in case of any sale or conveyance to another person, firm, or
corporation of the property of the Company as an entirety or substantially as an
entirety, the Warrantholder shall have the right, upon exercise of this Warrant,
to receive the kind and amount of securities and property (including cash)
receivable upon such consolidation, merger, sale or conveyance by a holder of
the number of shares of Common Stock or other securities into which such Warrant
might have been converted immediately prior to the consolidation, merger, sale,
or conveyance.

                  4.6      No Adjustment for Outstanding Exercise and Option
Rights and Certain Other Securities. No adjustment of the Warrant Price or
number of shares issuable upon exercise shall be made upon the issuance by the
Company of (1) Common Stock upon conversion or exchange of securities
convertible or exchangeable into Common Stock and outstanding on or before
February 3, 1989, (2) Common Stock upon exercise of any employee's stock option
outstanding on or before February 3, 1989, or (3) Common Stock or securities
convertible into Common Stock, or options to purchase Common Stock not included
in (1) or (2) above and not amounting to more than 10% of the Company's fully
diluted Common Stock issue, pursuant to an employee benefit plan of the Company.

         5.       Corporate Status of Shares To Be Issued. All shares of the
Company's Common Stock (or other securities in the event of an adjustment of the
Warrant Price or number of shares issuable upon exercise) which may be issued
upon the exercise of this Warrant shall, upon issuance and payment of the
Warrant Price, be fully paid and nonassessable.

         6.       Issuance of Stock Certificate. Upon the exercise of this
Warrant, the Company shall forthwith issue to the Warrantholder a certificate or
certificates representing the number of shares of its Common Stock (or other
securities in the event of an adjustment of the Warrant Price or number of
shares issuable upon exercise) to which the Warrant relates.

         7.       Partial Exercise and Exchange. Upon any partial exercise of
this Warrant, there shall be signed and issued to the Warrantholder a new
Warrant in respect of the Shares as to which this Warrant shall not have been
exercised. This Warrant may be exchanged, at the office of the Company by
surrender of this Warrant properly endorsed for transfer, exercise, or exchange,
for one or more new Warrants for the same aggregate number of Shares as
evidenced by the Warrant or Warrants exchanged.

         8.       Loss or Destruction of Warrant. The Company shall execute and
deliver a new Warrant of like tenor and date upon receipt by the Company of
evidence satisfactory to it of


                                      -3-
<PAGE>   10
the loss, theft, destruction or mutilation of this Warrant and, in the case of
loss, theft or destruction, of an indemnity by the original Warrantholder, or,
in case of any transfer, upon such terms as may be satisfactory to the Company,
or, in the case of mutilation, upon surrender and cancellation of this Warrant.

         9.       Status of Holder of Warrant. This Warrant shall not entitle
the Warrantholder to any voting rights or other rights as a shareholder of the
Company, and no dividends shall be payable or accrue in respect of this Warrant
or the securities issuable upon exercise, unless and until this Warrant is
exercised. Upon the exercise of this Warrant, the Warrantholder shall, to the
extent permitted by law, be deemed to be the holder of record of the shares of
Common Stock or other securities issuable upon such exercise, notwithstanding
that the stock transfer books of the Company are then closed or that the
certificates representing such shares of Common Stock or other securities are
not then actually delivered.

         10.      Reservation of Shares. The Company shall reserve out of its
authorized shares of Common Stock (and other securities in the event of an
adjustment of the Warrant Price or number of shares issuable upon exercise) a
number of shares sufficient to enable it to comply with its obligation to issue
the Shares (and other securities in the event of an adjustment of the Warrant
Price or number of shares issuable upon exercise) upon the exercise of this
Warrant.

         11.      Status Under Securities Laws.

                  11.1     No Registration. This Warrant has not been, and the
securities issuable upon exercise hereof will not be, registered under the
Securities Act of 1933 (the "1933 Act"), the Arizona Securities Act (the
"Arizona Act") or the securities laws of any other jurisdiction and must be held
indefinitely without any transfer, sale or other disposition unless subsequently
registered under the 1933 Act, the Arizona Act and the securities laws of any
other applicable jurisdiction or, in the opinion of counsel acceptable to the
Company, registration is not required under such Acts or laws.

                  11.2     Legend. There shall be endorsed on this Warrant and
on the certificates evidencing any securities issued upon the exercise of this
Warrant a legend substantially to the following effect:

                  "THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN
                  REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR
                  THE SECURITIES LAW OF ANY STATE. THE SECURITIES MAY NOT BE
                  SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED (EXCEPT TO A
                  COMMERCIAL BANK OR OTHER CORPORATION AFFILIATED WITH SECURITY
                  PACIFIC BANK ARIZONA) IN THE ABSENCE OF EFFECTIVE REGISTRATION
                  STATEMENTS OR AN OPINION OF COUNSEL ACCEPTABLE TO THIS COMPANY
                  THAT REGISTRATION IS NOT REQUIRED."

                  11.3     Restriction on Other Securities. Except upon certain
limited circumstances, the restrictions on the transfer of this Warrant and any
securities issued upon the


                                      -4-
<PAGE>   11
exercise of this Warrant will also apply to any and all shares of capital stock
or other securities issued or otherwise acquired on account of the exercise of
the Warrant including, without limitation, shares and securities issued or
acquired as a result of any stock dividend, stock split or exchange or any
distribution of shares or securities pursuant to any corporate reorganization,
reclassification or similar event.

                  11.4     Refusal to Transfer. The Company may refuse to effect
a transfer, sale or other disposition of this Warrant or any part thereof by the
Warrantholder or its successors or assigns except as expressly permitted by this
Warrant and the Agreement, which contains additional provisions governing any
transfer of this Warrant. The Company may also refuse to effect a transfer,
sale, or other disposition of any Shares or other securities issued upon
exercise of this Warrant which would be in violation of any express prohibition
in this Warrant or in the Agreement.

         12.      Governing Law. This Warrant is delivered and is intended to be
performed in the State of Arizona and shall be construed and enforced in
accordance with the laws of such state.

         13.      Execution. In witness whereof, the Company has caused this
Warrant to be signed by its duly authorized officers on __________, _____.

                                            ROCKFORD CORPORATION
[SEAL)


                                            By: /s/
                                               ----------------------
                                                     President

ATTEST:


/s/
----------------------
Assistant Secretary


                                      -5-
<PAGE>   12
                              ROCKFORD CORPORATION

                                  EXERCISE FORM

Rockford Corporation
648 South River Drive
Tempe, Arizona 85281

         The undersigned hereby irrevocably elects to exercise the right of
purchase represented by the attached Warrant, and to purchase thereunder, 43
shares of Common Stock (the "Shares") provided for therein, and requests that
certificates for the Shares be issued in the name of:

________________________________________________________________________________
         (Please Print Name, Address and Social Security Number)

________________________________________________________________________________
and, if said number of Shares shall not be all the Shares purchasable hereunder,
that a new Warrant certificate for the balance of the Shares purchasable under
the within Warrant certificate be registered in the name of the undersigned
Warrantholder or his Assignee as below indicated and delivered to the address
stated below.

         Dated:____________________________

         Name of Warrantholder or Assignee:_____________________________________
                                                     (Please Print)

Address:________________________________________________________________________

________________________________________________________________________________


Authorized Signature:___________________________________________________________

            Signature Guaranteed:_______________________________________________


                    Note:    The name of the Warrantholder must correspond with
                             the name as written upon the face of this Warrant
                             certificate in every particular, without alteration
                             or enlargement or any change whatever, unless this
                             Warrant has been assigned.


                                      -6-
<PAGE>   13
                                   ASSIGNMENT

                 (To be signed only upon assignment of Warrant)


  FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto

________________________________________________________________________________
             (Please Print Name, Address and Social Security Number)


a Warrant to purchase ________ shares of Common Stock and hereby irrevocably
constituting and appointing ______________________________ Attorney to transfer
said Warrant on the books of the Company, with full power of substitution in the
premises.



                                        ________________________________________
                                        Name of Registered Holder


         Dated: ________ 19___          ________________________________________
                                        Authorized Signature

            Signature Guaranteed:       ________________________________________


Note: The signature of this assignment must correspond with the name as written
above upon the fact of this Warrant certificate in every particular, without
alteration or enlargement of any change whatever.


                                      -7-