Exhibit 4.3


 


AMENDMENT NO. 3 TO AMENDMENT AGREEMENT
AND WAIVER


 


This AMENDMENT NO.
3 TO AMENDMENT AGREEMENT AND WAIVER (the “Amendment”), dated as of March 28, 2019, is made by and between
Ener-Core, Inc., a Delaware corporation, with headquarters located at 30100 Town Center Dr., Suite O-209, Laguna Niguel, California
92677 (the “Company”), and the investor listed on the signature page attached hereto (the “Holder”).


 


RECITALS


 


A. Reference is made
to that certain Securities Purchase Agreement dated as of September 19, 2017, by and among the Company, the Holder and the other
investors listed on the signature pages attached thereto and party to a joinder agreement thereto (as amended and/or restated
from time to time, the “Bridge SPA”); and the Senior Secured Notes issued to the Holder pursuant thereto (as
amended from time to time prior to the date hereof, the “Bridge Notes”);


 


B. Reference
is made to that certain Amendment Agreement and Waiver dated as of December 31, 2018 by and among the Company and the Holder with
respect to the Bridge SPA and the Bridge Notes (the “December Amendment”); and


 


C. In
compliance with Section 15 of the Bridge Notes and the Bridge SPA, this Amendment shall only be effective upon the
execution and delivery of this Amendment and agreements in form and substance identical to this Amendment (other than with
respect to the identity of the Holder and any provision regarding the reimbursement of legal fees) (together with this
Amendment, the “Amendments”) by the Required Holders (as defined in the Bridge Notes and Bridge SPA,
respectively) (such time, the “Effective Time”).


 


AGREEMENT


 


NOW THEREFORE,
in consideration of the foregoing mutual premises and the covenants and agreements hereinafter set forth, and for other good and
valuable consideration, the receipt, and legal adequacy of which is hereby acknowledged, the parties hereto, intending to be legally
bound, hereby agree as follows:


 


ARTICLE I


AMENDMENT


 


1. Amendment
of December Amendment. All references to the date “January 31, 2019” set forth in the December Amendment are hereby
amended to instead refer to the date “April 30, 2019”, and all references to the date “February 1, 2019” set
forth in the December Amendment are hereby amended to instead refer to the date “May 1, 2019”. Capitalized terms used
herein and not otherwise defined herein shall have the respective meanings set forth in the December Amendment.


 


ARTICLE II

MISCELLANEOUS


 


1. Effect
of this Amendment. This Amendment shall form a part of the Bridge Notes for all purposes, and each holder of Bridge Notes 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 Amendments substantially identical to this Amendment by the Company and the Required
Holders (as defined in the Bridge Notes and Bridge SPA, respectively). From and after such effectiveness, any reference to the
Bridge Notes shall be deemed to be a reference to the Bridge Notes, as amended hereby. Except as specifically amended as set forth
herein, each term and condition of the Bridge Notes shall continue in full force and effect.


 






    


     


    

 


2. Entire
Agreement. This Amendment, together with the Bridge SPA and Bridge Notes, as amended to date, contains the entire agreement
of the parties with respect to the matters contemplated hereby and thereby, and supersedes any prior or contemporaneous written
or oral agreements between them concerning the subject matter of this Amendment.


 


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


 


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 Page Follows]


 






    2 


     


    

 


IN WITNESS WHEREOF,
the Holder and the Company have caused their respective signature pages to this Amendment to be duly executed as of the date first
written above.


 


	 	COMPANY:
	 	 
	 	ENER-CORE, INC.
	 	 	
	 	By:	

	 	 	Name:	Domonic J. Carney
	 	 	Title:  	Chief Financial Officer


 





Signature
Page to amendment no. 3 to Amendment Agreement and Waiver—Bridge Notes


 






     


     


    

 





IN WITNESS WHEREOF,
the Holder and the Company have caused their respective signature pages to this Amendment to be duly executed as of the date first
written above.


 


	 	HOLDER:
	 	 	
	 	By:	

	 	   	Name:	    
	 	 	 	 


 





Signature
Page to amendment no. 3 to Amendment Agreement and Waiver—Bridge Notes