Exhibit 4.3


 





THIRD AMENDMENT TO


SENIOR SECURED NOTES


 


THIS THIRD AMENDMENT TO
SENIOR SECURED NOTES (this “Amendment”) is made and entered into as of December 30, 2015 by and among
Ener-Core, Inc., a Delaware corporation (the “Company”), and the undersigned, and amends those certain
Senior Secured Notes dated as of April 23, 2015 (as amended to date, the “Notes”) as issued by the Company
pursuant to that certain Securities Purchase Agreement, dated April 22, 2015, by and among the Company, the “Buyers”
identified therein, and the Collateral Agent identified therein (as amended to date, the “Agreement”).
Capitalized terms used herein but not otherwise defined herein shall have the meanings ascribed to such terms in the Notes.


 


RECITALS


 


WHEREAS, pursuant
to Section 15 of the Notes, the written consent of the holders of Notes representing at least a majority of the aggregate principal
amount of the Notes then outstanding, including Empery Asset Master, Ltd. (“Empery”) so long as Empery
or any of its Affiliates holds any Notes (the “Required Holders”), shall be required for any change or
amendment or waiver of any provision of the Notes, provided that any such amendment or waiver does not disproportionately, materially
and adversely affect the rights and obligations of any Holder relative to the comparable rights and obligations of the other Holders;


 


WHEREAS, any amendment
effected in accordance with Section 15 of the Notes is binding upon all holders of Notes; and


 


WHEREAS, the parties
hereto wish to amend the Notes as set forth below in order to facilitate the Company’s efforts to consummate a bridge financing
and subsequent Qualified Public Offering.


 


AGREEMENT


 


NOW, THEREFORE,
in consideration of the mutual covenants herein contained and other good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, the parties, intending to be legally bound, agree as follows:


 


ARTICLE
I

AMENDMENTS TO THE NOTES


 


Section 1.1 Qualified
Public Offering. Section 29(y) of the Notes is hereby amended and restated as follows:


 


“(t)“Qualified Public
Offering” means a sale of the Company's Common Stock and/or QPO Derivative Securities in a firm commitment underwritten
public offering registered under the Securities Act (other than a registration relating solely to a transaction under Rule 145
under the Securities Act (or any successor thereto) or to an employee benefit plan of the Company).”


 


Section 1.2 Cashless Exercise.
The following sentence is hereby added to the end of Section 3(a):


 


“If the form of QPO Derivative
Securities issued in the QPO do not include a cashless or net exercise provision, the Company shall include such a cashless or
net exercise provision in the form of such securities issuable upon conversion pursuant to this Section 3.”


 


Section 1.3 Removal of QPO Conversion
Limitation. Section 3(d)(ii) of the Notes is hereby deleted in full.


 


Section 1.4 Third
Tranche Notes. The defined term “Other Notes” shall include senior secured notes issued pursuant to the
Third Tranche Subscription as defined in that certain Fourth Amendment to Securities Purchase Agreement dated of even date herewith.


 






     


     


    

 


ARTICLE
II

MISCELLANEOUS


 


Section 2.1 Effect of
this Amendment. This Amendment shall form a part of each Note for all purposes, and each holder thereof shall be bound hereby.
This Amendment shall only be deemed to be in full force and effect from and after both the execution of this Amendment by the parties
hereto and the execution of agreements substantially identical to this Amendment by the Company and holders of Notes at least a
majority of the aggregate principal amount of the Notes then outstanding, including Empery, constituting the Required Holders.
From and after such effectiveness, any reference to the Notes shall be deemed to be a reference to the Notes as amended hereby.
Except as specifically amended as set forth herein, each term and condition of the Notes shall continue in full force and effect.


 


Section 2.2 Entire Agreement.
This Amendment, together with the Notes, contains the entire agreement of the parties and supersedes any prior or contemporaneous
written or oral agreements between them concerning the subject matter of this Amendment.


 


Section 2.3 Governing
Law. This Amendment shall be governed by the internal law of the State of New York.


 


Section 2.4 Counterparts.
This Amendment may be executed in any number of counterparts and by different parties hereto in separate counterparts, each of
which when so executed and delivered shall be deemed an original, but all such counterparts together shall constitute but one and
the same instrument; signature pages may be detached from multiple separate counterparts and attached to a single counterpart so
that all signature pages are physically attached to the same document. This Amendment may be executed by fax or electronic mail,
in PDF format, and no party hereto may contest this Amendment’s validity solely because a signature was faxed or otherwise
sent electronically.


 


[Signature Pages Follow]


 




    1


     


    

 





IN WITNESS WHEREOF,
the parties hereto have executed this Third Amendment to Senior Secured Notes as of the date first written above.


 


	 	COMPANY:
	 	 
	 	ENER-CORE, INC.
	 	 	 
	 	By:	 
	 	 	Name: Alain J. Castro
	 	 	Title: Chief Executive Officer 


 


 





[Signature Page to Third Amendment to Senior
Secured Notes—April 2015 Notes]


 




    2


     


    

 


IN WITNESS WHEREOF,
the parties hereto have executed this Third Amendment to Senior Secured Notes as of the date first written above.


 


	 	
        HOLDER:

         

        By:

         

	 	 	 
	 	By:	 
	 	 	Name: 
	 	 	Title: 


  


 





[Signature Page to Third Amendment to Senior
Secured Notes—April 2015 Notes]


 


 


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