Exhibit 10.4


 


SUBSIDIARY GUARANTEE


 


SUBSIDIARY GUARANTEE,
dated as of June 10, 2022 (this “Guarantee”), made by each of the signatories hereto (together with any other entity
that may become a party hereto as provided herein, the “Guarantors”), in favor of the purchasers signatory (together
with their permitted assigns, the “Purchasers”), to that certain Securities Purchase Agreement, dated as of the date
hereof, by and among Brain Scientific Inc., a Delaware corporation (the “Company”), and the Purchasers (the “Purchase
Agreement”).


 


W I T N E S S E T H:


 


WHEREAS, pursuant
to the Purchase Agreement, the Company has agreed to sell and issue to the Purchasers, and the Purchasers have agreed to purchase from
the Company the Debentures, subject to the terms and conditions set forth therein; and


 


WHEREAS, each
Guarantor will directly benefit from the extension of the loans to the Company represented by the issuance of the Debentures.


 


NOW, THEREFORE,
in consideration of the premises and to induce the Purchasers to enter into the Purchase Agreement and to carry out the transactions contemplated
thereby; each Guarantor hereby agrees with the Purchasers as follows:


 


1. Definitions.
Unless otherwise defined herein, terms defined in the Purchase Agreement and used herein shall have the meanings given to them in the
Purchase Agreement. The words “hereof,” “herein,” “hereto” and “hereunder”
and words of similar import when used in this Guarantee shall refer to this Guarantee as a whole and not to any particular provision of
this Guarantee, and Section and Schedule references are to this Guarantee unless otherwise specified. The meanings given to terms defined
herein shall be equally applicable to both the singular and plural forms of such terms. The following terms shall have the following meanings:


 


“Guarantee”
means this Subsidiary Guarantee, as the same may be amended, supplemented or otherwise modified from time to time.


 


“Obligations”
means, in addition to all other costs and expenses of collection incurred by Purchasers in enforcing any of such
“Obligations” (as defined in the Security Agreement) and/or this Guarantee, all of the liabilities and obligations
(primary, secondary, direct, contingent, sole, joint or several) due or to become due, or that are now or may be hereafter
contracted or acquired, or owing to, of the Company or any Guarantor to the Purchasers under this Guarantee, the Debentures and any
other instruments, agreements or other documents executed and/or delivered in connection herewith or therewith, in each case,
whether now or hereafter existing, voluntary or involuntary, direct or indirect, absolute or contingent, liquidated or unliquidated,
whether or not jointly owed with others, and whether or not from time to time decreased or extinguished and later increased, created
or incurred, and all or any portion of such obligations or liabilities that are paid, to the extent all or any part of such payment
is avoided or recovered directly or indirectly from any of the Purchasers as a preference, fraudulent transfer or otherwise as such
obligations may be amended, supplemented, converted, extended or modified from time to time. Without limiting the generality of the
foregoing, the term “Obligations” shall include, without limitation: (i) principal of, and interest on the
Debentures and the loans extended pursuant thereto, (ii) any and all other fees, indemnities, costs, obligations and liabilities of
the Company or any Guarantor from time to time under or in connection with this Guarantee, the Debentures and any other instruments,
agreements or other documents executed and/or delivered in connection herewith or therewith, and (iii) all amounts (including but
not limited to post-petition interest) in respect of the foregoing that would be payable but for the fact that the obligations to
pay such amounts are unenforceable or not allowable due to the existence of a bankruptcy, reorganization or similar proceeding
involving the Company or any Guarantor.


 






    


     


    

 


2. Guarantee.


 


(a) Guarantee.


 


(i) The Guarantors
hereby, jointly and severally, unconditionally and irrevocably, guarantee to the Purchasers and their respective successors, indorsees,
transferees and assigns, the prompt and complete payment and performance when due (whether at the stated maturity, by acceleration or
otherwise) of the Obligations.


 


(ii) Anything
herein or in any other Transaction Document to the contrary notwithstanding, the maximum liability of each Guarantor hereunder and under
the other Transaction Documents shall in no event exceed the amount which can be guaranteed by such Guarantor under applicable federal
and state laws, including laws relating to the insolvency of debtors, fraudulent conveyance or transfer or laws affecting the rights of
creditors generally (after giving effect to the right of contribution established in Section 2(b)).


 


(iii) Each Guarantor
agrees that the Obligations may at any time and from time to time exceed the amount of the liability of such Guarantor hereunder without
impairing the guarantee contained in this Section 2 or affecting the rights and remedies of the Purchasers hereunder.


 


(iv) The guarantee
contained in this Section 2 shall remain in full force and effect until all the Obligations and the obligations of each Guarantor
under the guarantee contained in this Section 2 shall have been satisfied by indefeasible payment in full.


 


(v) No payment
made by the Company, any of the Guarantors, any other guarantor or any other Person or received or collected by the Purchasers from the
Company, any of the Guarantors, any other guarantor or any other Person by virtue of any action or proceeding or any set-off or appropriation
or application at any time or from time to time in reduction of or in payment of the Obligations shall be deemed to modify, reduce, release
or otherwise affect the liability of any Guarantor hereunder which shall, notwithstanding any such payment (other than any payment made
by such Guarantor in respect of the Obligations or any payment received or collected from such Guarantor in respect of the Obligations),
remain liable for the Obligations up to the maximum liability of such Guarantor hereunder until the Obligations are indefeasibly paid
in full.


 






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(vi) Notwithstanding
anything to the contrary in this Guarantee, with respect to any defaulted non-monetary Obligations the specific performance of which by
the Guarantors is not reasonably possible (e.g., the issuance of the Company's Common Stock), the Guarantors shall only be liable for
making the Purchasers whole on a monetary basis for the Company's failure to perform such Obligations in accordance with the Transaction
Documents.


 


(b) Right of
Contribution. Subject to Section 2(c), each Guarantor hereby agrees that to the extent that a Guarantor shall have paid more
than its proportionate share of any payment made hereunder, such Guarantor shall be entitled to seek and receive contribution from and
against any other Guarantor hereunder which has not paid its proportionate share of such payment. Each Guarantor’s right of contribution
shall be subject to the terms and conditions of Section 2(c). The provisions of this Section 2(b) shall in no respect limit
the obligations and liabilities of any Guarantor to the Purchasers and each Guarantor shall remain liable to the Purchasers for the full
amount guaranteed by such Guarantor hereunder until the indefeasible repayment in full of all amounts owed under the Purchase Agreement,
the Debentures and the other Transaction Documents.


 


(c) No
Subrogation. Notwithstanding any payment made by any Guarantor hereunder or any set-off or application of funds of any Guarantor
by the Purchasers, no Guarantor shall be entitled to be subrogated to any of the rights of the Purchasers against the Company or any
other Guarantor or any collateral security or guarantee or right of offset held by the Purchasers for the payment of the
Obligations, nor shall any Guarantor seek or be entitled to seek any contribution or reimbursement from the Company or any other
Guarantor in respect of payments made by such Guarantor hereunder, until all amounts owing to the Purchasers by the Company on
account of the Obligations are indefeasibly paid in full. If any amount shall be paid to any Guarantor on account of such
subrogation rights at any time when all of the Obligations shall not have been paid in full, such amount shall be held by such
Guarantor in trust for the Purchasers, segregated from other funds of such Guarantor, and shall, forthwith upon receipt by such
Guarantor, be turned over to the Purchasers in the exact form received by such Guarantor (duly indorsed by such Guarantor to the
Purchasers, if required), to be applied against the Obligations, whether matured or unmatured, in such order as the Purchasers may
determine.


 


(d) Amendments,
Etc. With Respect to the Obligations. Each Guarantor shall remain obligated hereunder notwithstanding that, without any reservation
of rights against any Guarantor and without notice to or further assent by any Guarantor, any demand for payment of any of the Obligations
made by the Purchasers may be rescinded by the Purchasers and any of the Obligations continued, and the Obligations, or the liability
of any other Person upon or for any part thereof, or any collateral security or guarantee therefor or right of offset with respect thereto,
may, from time to time, in whole or in part, be renewed, extended, amended, modified, accelerated, compromised, waived, surrendered or
released by the Purchasers, and the Purchase Agreement and the other Transaction Documents and any other documents executed and delivered
in connection therewith may be amended, modified, supplemented or terminated, in whole or in part, as the Purchasers may deem advisable
from time to time, and any collateral security, guarantee or right of offset at any time held by the Purchasers for the payment of the
Obligations may be sold, exchanged, waived, surrendered or released. The Purchasers shall have no obligation to protect, secure, perfect
or insure any Lien at any time held by them as security for the Obligations or for the guarantee contained in this Section 2 or
any property subject thereto.


 






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(e) Guarantee
Absolute and Unconditional. Each Guarantor waives any and all notice of the creation, renewal, extension or accrual of any of
the Obligations and notice of or proof of reliance by the Purchasers upon the guarantee contained in this Section 2 or
acceptance of the guarantee contained in this Section 2; the Obligations, and any of them, shall conclusively be deemed to
have been created, contracted or incurred, or renewed, extended, amended or waived, in reliance upon the guarantee contained in this Section
2; and all dealings between the Company and any of the Guarantors, on the one hand, and the Purchasers, on the other hand,
likewise shall be conclusively presumed to have been had or consummated in reliance upon the guarantee contained in this Section
2. Each Guarantor waives to the extent permitted by law diligence, presentment, protest, demand for payment and notice of
default or nonpayment to or upon the Company or any of the Guarantors with respect to the Obligations. Each Guarantor understands
and agrees that the guarantee contained in this Section 2 shall be construed as a continuing, absolute and unconditional
guarantee of payment and performance without regard to: (a) the validity or enforceability of the Purchase Agreement or any other
Transaction Document, any of the Obligations or any other collateral security therefor or guarantee or right of offset with respect
thereto at any time or from time to time held by the Purchasers, (b) any defense, set-off or counterclaim (other than a defense of
payment or performance or fraud by Purchasers) which may at any time be available to or be asserted by the Company or any other
Person against the Purchasers, or (c) any other circumstance whatsoever (with or without notice to or knowledge of the Company or
such Guarantor) which constitutes, or might be construed to constitute, an equitable or legal discharge of the Company for the
Obligations, or of such Guarantor under the guarantee contained in this Section 2, in bankruptcy or in any other instance.
When making any demand hereunder or otherwise pursuing its rights and remedies hereunder against any Guarantor, the Purchasers may,
but shall be under no obligation to, make a similar demand on or otherwise pursue such rights and remedies as they may have against
the Company, any other Guarantor or any other Person or against any collateral security or guarantee for the Obligations or any
right of offset with respect thereto, and any failure by the Purchasers to make any such demand, to pursue such other rights or
remedies or to collect any payments from the Company, any other Guarantor or any other Person or to realize upon any such collateral
security or guarantee or to exercise any such right of offset, or any release of the Company, any other Guarantor or any other
Person or any such collateral security, guarantee or right of offset, shall not relieve any Guarantor of any obligation or liability
hereunder, and shall not impair or affect the rights and remedies, whether express, implied or available as a matter of law, of the
Purchasers against any Guarantor. For the purposes hereof, “demand” shall include the commencement and
continuance of any legal proceedings.


 


(f) Reinstatement.
The guarantee contained in this Section 2 shall continue to be effective, or be reinstated, as the case may be, if at any time
payment, or any part thereof, of any of the Obligations is rescinded or must otherwise be restored or returned by the Purchasers upon
the insolvency, bankruptcy, dissolution, liquidation or reorganization of the Company or any Guarantor, or upon or as a result of the
appointment of a receiver, intervenor or conservator of, or trustee or similar officer for, the Company or any Guarantor or any substantial
part of its property, or otherwise, all as though such payments had not been made.


 


(g) Payments.
Each Guarantor hereby guarantees that payments hereunder will be paid to the Purchasers without set-off or counterclaim in U.S. dollars
at the address set forth or referred to in the Signature Pages to the Purchase Agreement.


 






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3. Representations and Warranties.
Each Guarantor hereby makes the following representations and warranties to Purchasers as of the date hereof:


 


(a) Organization
and Qualification. The Guarantor is duly organized, validly existing and in good standing under the laws of the applicable
jurisdiction set forth on Schedule 1, with the requisite corporate power and authority to own and use its properties and
assets and to carry on its business as currently conducted. The Guarantor has no subsidiaries other than those identified as such on
the Disclosure Schedules to the Purchase Agreement. The Guarantor is duly qualified to do business and is in good standing as a
foreign corporation in each jurisdiction in which the nature of the business conducted or property owned by it makes such
qualification necessary, except where the failure to be so qualified or in good standing, as the case may be, could not,
individually or in the aggregate, (x) adversely affect the legality, validity or enforceability of any of this Guaranty in any
material respect, (y) have a material adverse effect on the results of operations, assets, prospects, or financial condition of the
Guarantor, or (z) adversely impair in any material respect the Guarantor's ability to perform fully on a timely basis its
obligations under this Guaranty (a “Material Adverse Effect”).


 


(b) Authorization;
Enforcement. The Guarantor has the requisite corporate power and authority to enter into and to consummate the transactions contemplated
by this Guaranty, and otherwise to carry out its obligations hereunder. The execution and delivery of this Guaranty by the Guarantor and
the consummation by it of the transactions contemplated hereby have been duly authorized by all requisite corporate action on the part
of the Guarantor. This Guaranty has been duly executed and delivered by the Guarantor and constitutes the valid and binding obligation
of the Guarantor enforceable against the Guarantor in accordance with its terms, except as such enforceability may be limited by applicable
bankruptcy, insolvency, reorganization, moratorium, liquidation or similar laws relating to, or affecting generally the enforcement of,
creditors' rights and remedies or by other equitable principles of general application.


 


(c) No Conflicts.
Except as disclosed in the Disclosure Schedules to the Purchase Agreement, the execution, delivery and performance of this Guaranty by
the Guarantor and the consummation by the Guarantor of the transactions contemplated thereby do not and will not: (i) conflict with or
violate any provision of its Certificate of Incorporation or By-laws or (ii) conflict with, constitute a default (or an event which with
notice or lapse of time or both would become a default) under, or give to others any rights of termination, amendment, acceleration or
cancellation of, any agreement, indenture or instrument to which the Guarantor is a party, or (iii) result in a violation of any law,
rule, regulation, order, judgment, injunction, decree or other restriction of any court or governmental authority to which the Guarantor
is subject (including Federal and State securities laws and regulations), or by which any material property or asset of the Guarantor
is bound or affected, except in the case of each of clauses (ii) and (iii), such conflicts, defaults, terminations, amendments, accelerations,
cancellations and violations as could not, individually or in the aggregate, have or result in a Material Adverse Effect. The business
of the Guarantor is not being conducted in violation of any law, ordinance or regulation of any governmental authority, except for violations
which, individually or in the aggregate, do not have a Material Adverse Effect.


 






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(d) Consents and
Approvals. Except as disclosed in the Disclosure Schedules to the Purchase Agreement, the Guarantor is not required to obtain any
consent, waiver, authorization or order of, or make any filing or registration with, any court or other federal, state, local, foreign
or other governmental authority or other person in connection with the execution, delivery and performance by the Guarantor of this Guaranty.


 


(e) Purchase
Agreement. The representations and warranties of the Company set forth in the Purchase Agreement as they relate to such Guarantor,
each of which is hereby incorporated herein by reference, are true and correct as of each time such representations are deemed to be made
pursuant to such Purchase Agreement, and the Purchasers shall be entitled to rely on each of them as if they were fully set forth herein,
provided that each reference in each such representation and warranty to the Company's knowledge shall, for the purposes of this Section
3, be deemed to be a reference to such Guarantor's knowledge.


 


(f) Foreign Law.
Each Guarantor has consulted with appropriate foreign legal counsel with respect to any of the above representations for which non-U.S.
law is applicable. Such foreign counsel has advised each applicable Guarantor that such counsel knows of no reason why any of the above
representations would not be true and accurate. Such foreign counsel was provided with copies of this Subsidiary Guarantee and the Transaction
Documents prior to rendering their advice.


 


4. Covenants.


 


(a) Each Guarantor
covenants and agrees with the Purchasers that, from and after the date of this Guarantee until the Obligations shall have been indefeasibly
paid in full, such Guarantor shall take, and/or shall refrain from taking, as the case may be, each commercially reasonable action that
is necessary to be taken or not taken, as the case may be, so that no Event of Default (as defined in the Debentures) is caused by the
failure to take such action or to refrain from taking such action by such Guarantor.


 


(b) So long as
any of the Obligations are outstanding, unless Purchasers holding at least 51% of the aggregate principal amount of the then outstanding
Debentures shall otherwise consent in writing, each Guarantor will not directly or indirectly on or after the date of this Guarantee:


 


i. other than Permitted
Indebtedness (as defined in the Debenture), enter into, create, incur, assume or suffer to exist any indebtedness for borrowed money of
any kind, including but not limited to, a guarantee, on or with respect to any of its property or assets now owned or hereafter acquired
or any interest therein or any income or profits therefrom;


 


ii. other than
Permitted Liens (as defined in the Debenture), enter into, create, incur, assume or suffer to exist any liens of any kind, on or with
respect to any of its property or assets now owned or hereafter acquired or any interest therein or any income or profits therefrom;


 










iii. amend
its certificate of incorporation, bylaws or other charter documents so as to adversely affect any rights of any Purchaser;


 


iv. repay,
repurchase or offer to repay, repurchase or otherwise acquire more than a de minimis number of shares of its securities or debt
obligations;


 


v. pay cash
dividends on any equity securities of such Guarantor other than dividends paid to another Guarantor or to the Company;


 






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vi. enter
into any transaction with any Affiliate of the Guarantor which would be required to be disclosed in any public filing of the Company with
the Commission, unless such transaction is made on an arm’s-length basis and expressly approved by a majority of the disinterested
directors of the Company (even if less than a quorum otherwise required for board approval); or


 


vii. enter
into any agreement with respect to any of the foregoing.


 


5. Miscellaneous.


 


(a) Amendments
in Writing. None of the terms or provisions of this Guarantee may be waived, amended, supplemented or otherwise modified except in
writing by the Purchasers holding a majority in principal amount of the outstanding Debentures.


 


(b) Notices.
All notices, requests and demands to or upon the Purchasers or any Guarantor hereunder shall be effected in the manner provided for in
the Purchase Agreement, provided that any such notice, request or demand to or upon any Guarantor shall be addressed to such Guarantor
at its notice address set forth on Schedule 5(b).


 


(c) No
Waiver By Course Of Conduct; Cumulative Remedies. The Purchasers shall not by any act (except by a written instrument pursuant
to Section 5(a)), delay, indulgence, omission or otherwise be deemed to have waived any right or remedy hereunder or to have
acquiesced in any default under the Transaction Documents or Event of Default. No failure to exercise, nor any delay in exercising,
on the part of the Purchasers, any right, power or privilege hereunder shall operate as a waiver thereof. No single or partial
exercise of any right, power or privilege hereunder shall preclude any other or further exercise thereof or the exercise of any
other right, power or privilege. A waiver by the Purchasers of any right or remedy hereunder on any one occasion shall not be
construed as a bar to any right or remedy which the Purchasers would otherwise have on any future occasion. The rights and remedies
herein provided are cumulative, may be exercised singly or concurrently and are not exclusive of any other rights or remedies
provided by law.


 


(d) Enforcement Expenses; Indemnification.


 


(i) Each Guarantor
agrees to pay, or reimburse the Purchasers for, all its costs and expenses incurred in collecting against such Guarantor under the guarantee
contained in Section 2 or otherwise enforcing or preserving any rights under this Guarantee and the other Transaction Documents
to which such Guarantor is a party, including, without limitation, the reasonable fees and disbursements of counsel to the Purchasers.


 


(ii) Each Guarantor
agrees to pay, and to save the Purchasers harmless from, any and all liabilities with respect to, or resulting from any delay in paying,
any and all stamp, excise, sales or other taxes which may be payable or determined to be payable in connection with any of the transactions
contemplated by this Guarantee.


 


(iii) Each Guarantor
agrees to pay, and to save the Purchasers harmless from, any and all liabilities, obligations, losses, damages, penalties, actions, judgments,
suits, costs, expenses or disbursements of any kind or nature whatsoever with respect to the execution, delivery, enforcement, performance
and administration of this Guarantee to the extent the Company would be required to do so pursuant to the Purchase Agreement.


 






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(iv) The agreements
in this Section shall survive repayment of the Obligations and all other amounts payable under the Purchase Agreement and the other Transaction
Documents.


 


(e) Successor
and Assigns. This Guarantee shall be binding upon the successors and assigns of each Guarantor and shall inure to the benefit of the
Purchasers and their respective successors and assigns; provided that no Guarantor may assign, transfer or delegate any of its rights
or obligations under this Guarantee without the prior written consent of the Purchasers.


 


(f) Set-Off.
Each Guarantor hereby irrevocably authorizes each Purchaser at any time and from time to time while an Event of Default under any of
the Transaction Documents shall have occurred and be continuing, without notice to such Guarantor or any other Guarantor, any such
notice being expressly waived by each Guarantor, to set-off and appropriate and apply any and all deposits, credits, indebtedness or
claims, in any currency, in each case whether direct or indirect, absolute or contingent, matured or unmatured, at any time held or
owing by such Purchaser to or for the credit or the account of such Guarantor, or any part thereof in such amounts as such Purchaser
may elect, against and on account of the obligations and liabilities of such Guarantor to the Purchaser hereunder and claims of
every nature and description of such Purchaser against such Guarantor, in any currency, whether arising hereunder, under the
Purchase Agreement, any other Transaction Document or otherwise, as such Purchaser may elect, whether or not such Purchaser has made
any demand for payment and although such obligations, liabilities and claims may be contingent or unmatured. A Purchaser shall
notify such Guarantor and the Agent named in the Security Agreement promptly of any such set-off and the application made by such
Purchaser of the proceeds thereof, provided that the failure to give such notice shall not affect the validity of such set-off and
application. The rights of the Purchasers under this Section are in addition to other rights and remedies (including, without
limitation, other rights of set-off) which the Purchasers may have.


 


(g) Counterparts.
This Guarantee may be executed by one or more of the parties to this Guarantee on any number of separate counterparts (including by telecopy),
and all of said counterparts taken together shall be deemed to constitute one and the same instrument.


 


(h) Severability.
Any provision of this Guarantee which is prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the extent of such prohibition or unenforceability without invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render unenforceable such provision in any other jurisdiction.


 


(i) Section Headings.
The Section headings used in this Guarantee are for convenience of reference only and are not to affect the construction hereof or be
taken into consideration in the interpretation hereof.


 


(j) Integration.
This Guarantee and the other Transaction Documents represent the agreement of the Guarantors and the Purchasers with respect to the subject
matter hereof and thereof, and there are no promises, undertakings, representations or warranties by the Purchasers relative to subject
matter hereof and thereof not expressly set forth or referred to herein or in the other Transaction Documents.


 






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(k) Governing
Laws. All questions concerning the construction, validity, enforcement and interpretation of this Guarantee shall be governed by
and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of
conflicts of law thereof. Each of the Company and the Guarantors agree that all proceedings concerning the interpretations,
enforcement and defense of the transactions contemplated by this Guarantee (whether brought against a party hereto or its respective
affiliates, directors, officers, shareholders, partners, members, employees or agents) shall be commenced exclusively in the state
and federal courts sitting in the City of New York, Borough of Manhattan. Each of the Company and the Guarantors hereby irrevocably
submits to the exclusive jurisdiction of the state and federal courts sitting in the City of New York, Borough of Manhattan for the
adjudication of any dispute hereunder or in connection herewith or with any transaction contemplated hereby or discussed herein, and
hereby irrevocably waives, and agrees not to assert in any proceeding, any claim that it is not personally subject to the
jurisdiction of any such court, that such proceeding is improper. Each party hereto hereby irrevocably waives personal service of
process and consents to process being served in any such proceeding by mailing a copy thereof via registered or certified mail or
overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Guarantee and
agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall
be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto hereby irrevocably
waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of
or relating to this Guarantee or the transactions contemplated hereby.


 


(l) Acknowledgements. Each Guarantor
hereby acknowledges that:


 


(i) it has been
advised by counsel in the negotiation, execution and delivery of this Guarantee and the other Transaction Documents to which it is a party;


 


(ii) the Purchasers
have no fiduciary relationship with or duty to any Guarantor arising out of or in connection with this Guarantee or any of the other Transaction
Documents, and the relationship between the Guarantors, on the one hand, and the Purchasers, on the other hand, in connection herewith
or therewith is solely that of debtor and creditor; and


 


(iii) no joint
venture is created hereby or by the other Transaction Documents or otherwise exists by virtue of the transactions contemplated hereby
among the Guarantors and the Purchasers.


 


(m) Additional
Guarantors. The Company shall cause each of its subsidiaries formed or acquired on or subsequent to the date hereof to become a Guarantor
for all purposes of this Guarantee by executing and delivering an Assumption Agreement in the form of Annex 1 hereto.


 


(n) Release
of Guarantors. Each Guarantor will be released from all liability hereunder concurrently with the indefeasible repayment in full of
all amounts owed under the Purchase Agreement, the Debentures and the other Transaction Documents.


 


(o) Seniority.
The Obligations of each of the Guarantors hereunder rank senior in priority to any other Indebtedness (as defined in the Purchase Agreement)
of such Guarantor.


 


(p)
WAIVER OF JURY TRIAL. EACH GUARANTOR AND, BY ACCEPTANCE OF THE BENEFITS HEREOF, THE PURCHASERS, HEREBY IRREVOCABLY AND UNCONDITIONALLY
WAIVE TRIAL BY JURY IN ANY LEGAL ACTION OR PROCEEDING RELATING TO THIS GUARANTEE AND FOR ANY COUNTERCLAIM THEREIN.


 


*********************


 


(Signature Pages Follow)


 






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IN WITNESS WHEREOF, each of the undersigned
has caused this Guarantee to be duly executed and delivered as of the date first above written.


 


	PIEZO MOTION CORP.	 
	 	 	 
	By:	 	 
		Name:	 
		Title: President	 
	 	 	 
	MEMORY MD, INC. 	 
	 	 	 
	By:	 	 
		Name:	 
		Title: President	 


 


SCHEDULE 1


 


GUARANTORS


 


The following are the names, notice
addresses and jurisdiction of organization of each Guarantor.


 


	Name	Notice Addresses	Jurisdiction of Organization
	
    Piezo
    Motion Corp.

     
	c/o Brain Scientific Inc.,6700 Professional Parkway, Lakewood Ranch, FL 34240	Delaware
	Memory MD, Inc.	c/o Brain Scientific Inc.,6700 Professional Parkway, Lakewood Ranch, FL 34240	Delaware



 






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Annex 1 to


SUBSIDIARY GUARANTEE


 


ASSUMPTION AGREEMENT, dated as
of          , made by          , a corporation (the “Additional Guarantor”), in favor of the Purchasers pursuant to the Purchase
Agreement referred to below. All capitalized terms not defined herein shall have the meaning ascribed to them in such Purchase
Agreement.


 


W I T N E S S E T H :


 


WHEREAS, Brain Scientific Inc., a
Delaware corporation (the “Company”), and the Purchasers have entered into that certain Securities Purchase Agreement,
dated as of June          , 2022 (as amended, supplemented or otherwise modified from
time to time, the “Purchase Agreement”);


 


WHEREAS, in
connection with the Purchase Agreement, the Subsidiaries of the Company have entered into the Subsidiary Guarantee, dated as of June ,
2022 (as amended, supplemented or otherwise modified from time to time, the “Guarantee”) in favor of the Purchasers;


 


WHEREAS, the Purchase Agreement requires
the Additional Guarantor to become a party to the Guarantee; and


 


WHEREAS, the Additional Guarantor
has agreed to execute and deliver this Assumption Agreement in order to become a party to the Guarantee;


 


NOW, THEREFORE, IT IS AGREED:


 


1. Guarantee.
By executing and delivering this Assumption Agreement, the Additional Guarantor, as provided in Section 5(m) of the Guarantee,
hereby becomes a party to the Guarantee as a Guarantor thereunder with the same force and effect as if originally named therein as a Guarantor
and, without limiting the generality of the foregoing, hereby expressly assumes all obligations and liabilities of a Guarantor thereunder.
The information set forth in Annex 1 hereto is hereby added to the information set forth in Schedule 1 to the Guarantee.
The Additional Guarantor hereby represents and warrants that each of the representations and warranties contained in Section 3
of the Guarantee is true and correct on and as the date hereof as to such Additional Guarantor (after giving effect to this Assumption
Agreement) as if made on and as of such date.


 


2. Governing Law.
THIS ASSUMPTION AGREEMENT SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.


 






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IN WITNESS WHEREOF, the undersigned
has caused this Assumption Agreement to be duly executed and delivered as of the date first above written.


 


 


	 	[ADDITIONAL GUARANTOR]
	 	 	 
	 	By:	                                  
	 	Name:	 
	 	Title:	 


 


 


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