Document:

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                                                          American National Bank
                                                    and Trust Company of Chicago

                           PROMISSORY NOTE (SECURED)

$1,500,000.00                              Chicago, Illinois    December 6, 1999

                                                        Due:   November 30, 2000

        FOR VALUE RECEIVED, the undersigned (jointly and severally if more than
one) ("Borrower"), promises to pay to the order of AMERICAN NATIONAL BANK AND
TRUST COMPANY OF CHICAGO ("Bank"), at its principal place of business in
Chicago, Illinois or such other place as Bank may designate from time to time
hereafter, the principal sum of ONE MILLION FIVE HUNDRED THOUSAND AND 00/100
DOLLARS, or such lesser principal sum as may then be owed by Borrower to Bank
hereunder, which sum shall be due and payable on NOVEMBER 30, 2000.

        This Note restates and replaces a PROMISSORY NOTE (SECURED) in the
principal amount of $1,500,000.00, dated July 31, 1998 executed by Borrower in
favor of Bank (the "Prior Note") and is not a repayment or novation of the Prior
Note.

        Borrower's obligations and liabilities to Bank under this Note, and all
other obligations and liabilities of Borrower to Bank (including without
limitation all debts, claims and indebtedness) whether primary, secondary,
direct, contingent, fixed or otherwise, including those evidenced in rate
hedging agreements designed to protect the Borrower from the fluctuation of
interest rates, heretofore, now and/or from time to time hereafter owing, due or
payable, however evidenced, created, incurred, acquired or owing and however
arising, whether under this Note, any agreement, instrument or document
heretofore, now or from time to time hereafter executed and delivered to Bank by
or on behalf of Borrower, or by oral agreement or operation of law or otherwise
shall be defined and referred to herein as "Borrower's Liabilities".

        The unpaid principal balance of Borrower's Liabilities due hereunder
shall bear interest from the date of disbursement until paid, computed as
follows AT A DAILY RATE EQUAL TO THE DAILY RATE EQUIVALENT OF 0.50% PER ANNUM IN
EXCESS OF the rate of interest announced or published publicly from time to time
by Bank as its prime or base rate of interest (THE "BASE RATE") (computed on the
basis of a 360-day year and actual days elapsed); provided, however, that in the
event that any of Borrower's Liabilities are not paid when due, the unpaid
amount of Borrower's Liabilities shall bear interest after the due date until
paid at a rate equal to the sum of the rate that would otherwise be in effect
plus 3%.

        The rate of interest to be charged by Bank to Borrower shall fluctuate
hereafter from time to time concurrently with, and in an amount equal to, each
increase or decrease in the Base Rate, whichever is applicable.

        Accrued interest shall be payable by Borrower to Bank on the same day of
each month, and at maturity, commencing with the LAST DAY OF DECEMBER, 1999, or
as billed by Bank to Borrower, at Bank's principal place of business, or at such
other place as Bank may designate from time to time hereafter. After maturity,
accrued interest on all of Borrower's Liabilities shall be due and payable on
demand.

        Borrower warrants and represents to Bank that Borrower shall use the
proceeds represented by this Note solely for proper business purposes and
consistently with all applicable laws and statutes.

        To secure the prompt payment to Bank of Borrower's Liabilities and the
prompt, full and faithful performance by Borrower of all of the provisions to be
kept, observed or performed by Borrower under this Note and/or any other
agreement, instrument or document heretofore, now and/or from time to time
hereafter delivered by or on behalf of Borrower to Bank, Borrower grants to Bank
a security interest in and to the following property: (a) all of Borrower's now
existing and/or owned and hereafter arising or acquired monies, reserves,
deposits, deposit accounts and interest or dividends thereon, securities, cash,
cash equivalents and other property now or at any time or times hereafter in the
possession or under the control of Bank or its bailee for any purpose; (b) ALL
BUSINESS ASSETS OF THE LANGER BIOMECHANICS GROUP, INC., A NEW YORK CORPORATION,
PURSUANT TO LOAN AND SECURITY AGREEMENT DATED NOVEMBER 30, 1999, AS AMENDED FROM
TIME TO TIME, BY AND BETWEEN BORROWER AND BANK; and (c) all substitutions,
renewals, improvements, accessions or additions thereto, replacements,
offspring, rents, issues, profits, returns, products and proceeds thereof,
including without limitation proceeds of insurance policies insuring the
foregoing collateral (all of the foregoing property is referred to herein
individually and collectively as "Collateral").

        Regardless of the adequacy of the Collateral, any deposits or other sums
at any time credited by or payable or due from Bank to Borrower, or any monies,
cash, cash equivalents, securities, instruments, documents or other assets of
Borrower in the possession or control of Bank or its bailee for any purpose, may
be reduced to cash and applied by Bank to or setoff by Bank against Borrower's
Liabilities.

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        Borrower agrees to deliver to Bank immediately upon Bank's demand, such
additional collateral as Bank may request from time to time should the value of
the Collateral (in Bank's sole and exclusive opinion) decline, deteriorate,
depreciate or become impaired, or should Bank deem itself insecure for any
reason whatsoever, including without limitation a change in the financial
condition of Borrower or any party liable with respect to Borrower's
Liabilities, and does hereby grant to Bank a continuing security interest in
such other collateral, which shall be deemed to be a part of the Collateral.
Borrower shall execute and deliver to Bank, at any time upon Bank's demand, all
agreements, instruments, documents and other written matter that Bank may
request, in form and substance acceptable to Bank, to perfect and maintain
perfected Bank's security interest in the Collateral or any additional
collateral. Borrower agrees that a carbon, photographic or photostatic copy, or
other reproduction, of this Note or of any financing statement, shall be
sufficient as a financing statement.

        Bank may take, and Borrower hereby waives notice of, any action from
time to time that Bank may deem necessary or appropriate to maintain or protect
the Collateral, and Bank's security interest therein, and in particular Bank may
at any time (i) transfer the whole or any part of the Collateral into the name
of the Bank or its nominee, (ii) collect any amounts due on Collateral directly
from persons obligated thereon, (iii) take control of any proceeds and products
of Collateral, and/or (iv) sue or make any compromise or settlement with respect
to any Collateral. Borrower hereby releases Bank from any and all causes of
action or claims which Borrower may now or hereafter have for any asserted loss
or damage to Borrower claimed to be caused by or arising from: (a) Bank's taking
any action permitted by this paragraph; (b) any failure of Bank to protect,
enforce or collect in whole or in part any of the Collateral; and/or (c) any
other act or omission to act on the part of Bank, its officers, agents or
employees, except for willful misconduct.

        The occurrence of any one of the following events shall constitute a
default by the Borrower ("Event of Default") under this Note if not cured within
seven (7) business days, where applicable: (a) if Borrower fails to pay any of
Borrower's Liabilities when due and payable or declared due and payable (whether
by scheduled maturity, required payment, acceleration, demand or otherwise); (b)
if Borrower or any guarantor of any of Borrower's Liabilities fails or neglects
to perform, keep or observe any material term, provision, condition, covenant,
warranty or representation contained in this Note; (c) occurrence of a material
default or event of default under any agreement, instrument or document
heretofore, now or at any time hereafter delivered by or on behalf of Borrower
to Bank; (d) occurrence of a material default or an event of default under any
agreement, instrument or document heretofore, now or at any time hereafter
delivered to Bank by any guarantor of Borrower's Liabilities or by any person or
entity which has granted to Bank a security interest or lien in and to some or
all of such person's or entity's real or personal property to secure the payment
of Borrower's Liabilities; (e) if the Collateral or any other of Borrower's
assets are attached, seized, subjected to a writ, or are levied upon or become
subject to any lien or come within the possession of any receiver, trustee,
custodian or assignee for the benefit of creditors; (f) if a material notice of
lien, levy or assessment is filed of record or given to Borrower with respect to
all or any of Borrower's assets by any federal, state or local department or
agency; (g) if Borrower or any guarantor of Borrower's Liabilities becomes
insolvent or generally fails to pay or admits in writing its inability to pay
debts as they become due, if a petition under Title 11 of the United States Code
or any similar law or regulation is filed by or against Borrower or any such
guarantor, if Borrower or any such guarantor shall make an assignment for the
benefit of creditors, if any case or proceeding is filed by or against Borrower
or any such guarantor for its dissolution or liquidation, or if Borrower or any
such guarantor is enjoined, restrained or in any way prevented by court order
from conducting all or any material part of its business affairs; (h) the death
or incompetency of Borrower or any guarantor of Borrower's Liabilities, or the
appointment of a conservator for all or any portion of Borrower's assets or the
Collateral; (i) the revocation, termination or cancellation of any guaranty of
Borrower's Liabilities without written consent of Bank; (j) if a contribution
failure occurs with respect to any pension plan maintained by Borrower or any
corporation, trade or business that is, along with Borrower, a member of a
controlled group of corporations or a controlled group of trades or businesses
(as described in Sections 414(b) and (c) of the Internal Revenue Code of 1986 or
Section 4001 of the Employee Retirement Income Security Act of 1974, as amended,
"ERISA") sufficient to give rise to a lien under Section 302(f) of ERISA; (k) if
Borrower or any guarantor of Borrower's Liabilities is in default in the payment
of any obligations, indebtedness or other liabilities to any third party and
such default is declared and is not cured within the time, if any, specified
therefor in any agreement governing the same; or (l) if any material statement,
report or certificate made or delivered by Borrower, any of Borrower's partners,
officers, employees or agents or any guarantor of Borrower's Liabilities is not
true and correct.

        Upon the occurrence of an Event of Default, at Bank's option, without
notice by Bank to or demand by Bank of Borrower: (i) all of Borrower's
Liabilities shall be immediately due and payable; (ii) Bank may exercise any one
or more of the rights and remedies accruing to a secured party under the Uniform
Commercial Code of the relevant jurisdiction and any other applicable law upon
default by a debtor; (iii) Bank may enter, with or without process of law and
without breach of the peace, any premises where the Collateral is or may be
located, and may seize or remove the Collateral from said premises and/or remain
upon said premises and use the same for the purpose of collecting, preparing and
disposing of the Collateral; and/or (iv) Bank may sell or otherwise dispose of
the Collateral at public or private sale for cash or credit, provided, however,
that Borrower shall be credited with the net proceeds of any such sale only when
the same are actually received by Bank.

        Upon an Event of Default, Borrower, immediately upon demand by Bank,
shall assemble the Collateral and make it available to Bank at a place or places
to be designated by Bank which is reasonably convenient to Bank and Borrower.

                                       2
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        All of Bank's rights and remedies under this Note are cumulative and
non-exclusive. The acceptance by Bank of any partial payment made hereunder
after the time when any of Borrower's Liabilities become due and payable will
not establish a custom or waive any rights of Bank to enforce prompt payment
hereof. Bank's failure to require strict performance by Borrower of any
provision of this Note shall not waive, affect or diminish any right of Bank
thereafter to demand strict compliance and performance therewith. Any waiver of
an Event of Default hereunder shall not suspend, waive or affect any other Event
of Default hereunder. Borrower and every endorser waive presentment, demand and
protest and notice of presentment, protest, default, non-payment, maturity,
release, compromise, settlement, extension or renewal of this Note, and hereby
ratify and confirm whatever Bank may do in this regard. Borrower further waives
any and all notice or demand to which Borrower might be entitled with respect to
this Note by virtue of any applicable statute or law (to the extent permitted by
law).
        Borrower agrees to pay, immediately upon demand by Bank, any and all
costs, fees and expenses (including reasonable attorneys' fees, costs and
expenses) incurred by Bank (i) in enforcing any of Bank's rights hereunder, and
(ii) in representing Bank in any litigation, contest, suit or dispute, or to
commence, defend or intervene or to take any action with respect to any
litigation, contest, suit or dispute (whether instituted by Bank, Borrower or
any other person) in any way relating to this Note, Borrower's Liabilities or
the Collateral, and to the extent not paid the same shall become part of
Borrower's Liabilities.
        This Note shall be deemed to have been submitted by Borrower to Bank and
to have been made at Bank's principal place of business. This Note shall be
governed and controlled by the internal laws of the State of Illinois and not
the law of conflicts.
        Advances under this Note may be made by Bank upon oral or written
request of any person authorized to make such requests on behalf of Borrower
("Authorized Person"). Borrower agrees that Bank may act on requests which Bank
in good faith believes to be made by an Authorized Person, regardless of whether
such requests are in fact made by an Authorized Person. Any such advance shall
be conclusively presumed to have been made by Bank to or for the benefit of
Borrower. Borrower does hereby irrevocably confirm, ratify and approve all such
advances by Bank and agrees to indemnify Bank against any and all losses and
expenses (including reasonable attorneys' fees) and shall hold Bank harmless
with respect thereto.

        TO INDUCE BANK TO ACCEPT THIS NOTE, BORROWER IRREVOCABLY AGREES THAT,
SUBJECT TO BANK'S SOLE AND ABSOLUTE ELECTION, ALL ACTIONS OR PROCEEDINGS IN ANY
WAY, MANNER OR RESPECT, ARISING OUT OF OR FROM OR RELATED TO THIS NOTE SHALL BE
LITIGATED IN COURTS HAVING SITUS WITHIN THE CITY OF CHICAGO, STATE OF ILLINOIS.
BORROWER HEREBY CONSENTS AND SUBMITS TO THE JURISDICTION OF ANY LOCAL, STATE OR
FEDERAL COURT LOCATED WITHIN SAID CITY AND STATE. BORROWER HEREBY WAIVES ANY
RIGHT IT MAY HAVE TO TRANSFER OR CHANGE THE VENUE OF ANY LITIGATION BROUGHT
AGAINST BORROWER BY BANK IN ACCORDANCE WITH THIS PARAGRAPH.

        BORROWER IRREVOCABLY WAIVES ANY RIGHT TO TRIAL BY JURY IN ANY ACTION,
SUIT, COUNTERCLAIM OR PROCEEDING (i) TO ENFORCE OR DEFEND ANY RIGHTS UNDER OR IN
CONNECTION WITH THIS NOTE OR ANY AMENDMENT, INSTRUMENT, DOCUMENT OR AGREEMENT
DELIVERED OR WHICH MAY IN THE FUTURE BE DELIVERED IN CONNECTION HEREWITH, OR
(ii) ARISING FROM ANY DISPUTE OR CONTROVERSY IN CONNECTION WITH OR RELATED TO
THIS NOTE OR ANY SUCH AMENDMENT, INSTRUMENT, DOCUMENT OR AGREEMENT, AND AGREES
THAT ANY SUCH ACTION, SUIT, COUNTERCLAIM OR PROCEEDING SHALL BE TRIED BEFORE A
COURT AND NOT BEFORE A JURY.

                                             BORROWER:

Address: 450 COMMACK ROAD                    THE LANGER BIOMECHANICS GROUP, INC.
         DEER PARK, NEW YORK 11729           a New York corporation

                                         By:
                                             -----------------------------------
                                                               PRESIDENT/CHIEF
                                             DANIEL J. GORNEY  EXECUTIVE OFFICER
                                             -----------------------------------
                                             Printed Name                Title

                                         By:
                                             -----------------------------------
                                                         CHIEF FINANCIAL OFFICER
                                             THOMAS G. ARCHBOLD
                                             -----------------------------------
                                             Printed Name                Title
                                             Tax I.D. Number:  11-2239561

Scott J. Buechler/8462

                                       3<PAGE>

                                  EXHIBIT 4.3
          COPY OF THE PARTNERSHIP'S CERTIFICATE OF LIMITED PARTNERSHIP

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                               STATE OF DELAWARE

                       CERTIFICATE OF LIMITED PARTNERSHIP

                                       OF

                         ICON INCOME FUND EIGHT B L.P.

    The Undersigned, desiring to form a limited partnership pursuant to the
provisions of the Delaware Revised Uniform Limited Partnership Act, 6 Delaware
Code, Chapter 17, do hereby certify as follows:

    1.  FIRST: The name of the limited partnership is "ICON Income Fund Eight B
       L.P."

    2.  SECOND: The name and address of the Registered Agent is Corporation
       Service Company, 1013 Centre Road, Wilmington, (County of New Castle)
       Delaware 19805

    3.  THIRD: The name and mailing address of each general partner is as
       follows:

                               111 Church Street
                             White Plains, NY 10601

    IN WITNESS WHEREOF, the undersigned has executed this Certificate of Limited
Partnership of ICON Income Fund Eight B L.P. as of this 7th day of February,
2000.

                                          ICON Income Fund Eight B L.P.
                                          By its General Partner, ICON Captial
                                          Corp.

                                          /s/ THOMAS W. MARTIN
                                          --------------------------------------
                                          Thomas W. Martin
                                          EXECUTIVE VICE PRESIDENT

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