B. Riley Principal Merger Corp. II Contracts & Agreements

Amendment No. 1 to Sales Agreement, dated August (Filed With SEC on August 23, 2023)

Indenture, dated May 25, 2023, between the Company and Wilmington Trust, National Association, as trustee (Filed With SEC on May 25, 2023)

Form of Securities Purchase Agreement, dated as of May 15, 2023 (Filed With SEC on May 17, 2023)

Form of Common Stock Purchase Warrant (Filed With SEC on May 17, 2023)

Form of Securities Purchase Agreement, dated as of April 12, 2023 (Filed With SEC on April 14, 2023)

Form of Common Stock Purchase Warrant (Filed With SEC on April 14, 2023)

Fourth Supplemental Agreement, dated as of April 10, 2023, to the Standby Equity Purchase Agreement dated as of April 28, 2022 between Eos Energy Enterprises, Inc. and YA II PN,... (Filed With SEC on April 11, 2023)

Amendment No. 5 dated as of April 10, 2023 to the Standby Equity Purchase Agreement dated as of April 28, 2022 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on April 11, 2023)

Convertible Promissory Note dated as of April 10, 2023 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on April 11, 2023)

Third Supplemental Agreement dated as of March 17, 2023 to the Standby Equity Purchase Agreement dated as of April 28, 2022 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on March 17, 2023)

Amendment No. 4 dated as of March 17, 2023 to the Standby Equity Purchase Agreement dated as of April 28, 2022 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on March 17, 2023)

Convertible Promissory Note dated as of March 17, 2023 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on March 17, 2023)

Convertible Promissory Note dated as of February 1, 2023 made by Eos Energy Enterprises, Inc. in favor of YA II PN, LTD (Filed With SEC on February 2, 2023)

Employment Agreement dated January 20, 2023 (Filed With SEC on January 23, 2023)

Separation Agreement dated January 20, 2023 (Filed With SEC on January 23, 2023)

Limited Consent Agreement, dated as of January 17, 2023, among Eos Energy Enterprises, LLC, the lenders party thereto, and ACP Post Oak Credit I LLC, as administrative agent (Filed With SEC on January 19, 2023)

Investment Agreement, dated January 18, 2023, by and among Eos Energy Enterprises, LLC and the purchasers listed therein (Filed With SEC on January 19, 2023)

Form of Note (including Indenture incorporated by reference therein) (Filed With SEC on January 19, 2023)

Second Supplemental Agreement dated as of December 29, 2022 to the Standby Equity Purchase Agreement dated as of April 28, 2022 between Eos Energy Enterprises, Inc. and YA II PN,... (Filed With SEC on December 29, 2022)

Amendment No. 3 dated as of December 29, 2022 to the Standby Equity Purchase Agreement dated as of April 28, 2022 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on December 29, 2022)

Convertible Promissory Note dated as of December 29, 2022 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on December 29, 2022)

Commitment Increase Agreement, dated as of December 7, 2022, by and among Eos Energy Enterprises, Inc., the guarantors party thereto, and ACP Post Oak Credit I LLC (Filed With SEC on December 8, 2022)

Amendment No. 2 to the Standby Equity Purchase Agreement dated as of November 14, 2022 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on November 14, 2022)

Amended Director Compensation Policy (Filed With SEC on September 9, 2022)

Sales Agreement, dated August 5, 2022, by and between Eos Energy Enterprises, Inc. and Cowen and Company, LLC (Filed With SEC on August 5, 2022)

Commitment Increase Agreement, dated as of August (Filed With SEC on August 5, 2022)

Joinder to Investment Agreement, dated May 1, 2022 among Eos Energy Enterprises, Inc., Spring Creek Capital, LLC and Wood River Capital, LLC (Filed With SEC on August 1, 2022)

Supplemental Agreement dated as of June 13, 2022 to the Standby Equity Purchase Agreement dated as of April 28, 2022 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on June 13, 2022)

Amendment No. 1 to the Standby Equity Purchase Agreement dated as of April 28, 2022 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on June 13, 2022)

Convertible Promissory Note dated as of June 13, 2022 between Eos Energy Enterprises, Inc. and YA II PN, LTD (Filed With SEC on June 13, 2022)

Joinder to Investment Agreement, dated May 1, 2022 among Eos Energy Enterprises, Inc., Spring Creek Capital, LLC (Filed With SEC on May 9, 2022)

Standby Equity Purchase Agreement, dated (Filed With SEC on April 28, 2022)

Indenture, dated April 7, 2022, between the Company and Wilmington Trust, National Association, as trustee (Filed With SEC on April 13, 2022)

Description of Securities (Filed With SEC on February 25, 2022)

Employment Letter (Filed With SEC on February 14, 2022)

Employment Agreement dated December 13, 2021 (Filed With SEC on December 14, 2021)

Separation Agreement dated December 13, 2021 (Filed With SEC on December 14, 2021)

Guaranty dated September 30, 2021 (Filed With SEC on October 5, 2021)

Master Equipment Financing Agreement dated September 30, 2021 (Filed With SEC on October 5, 2021)

Investment Agreement, dated as of July 6, 2021, among Eos Energy Enterprises, Inc. and Spring Creek Capital, LLC (Filed With SEC on July 7, 2021)

Form of Note (including Indenture incorporated by reference therein) (Filed With SEC on July 7, 2021)

Amended and Restated Registration Rights Agreement, dated (Filed With SEC on May 10, 2021)

Unit Purchase Agreement, dated April (Filed With SEC on April 14, 2021)

Employment Agreement, dated March 25, 2021 by and between the Company and Sagar Kurada (Filed With SEC on March 31, 2021)

Offer Letter, dated February 19, 2021 by and between the Company and Jody Markopoulos (Filed With SEC on March 12, 2021)

Description of Securities (Filed With SEC on February 26, 2021)

Non-Employee Director Compensation Policy (Filed With SEC on December 14, 2020)

Director Form Option Award Agreement (Filed With SEC on December 14, 2020)

Director Form Restricted Stock Unit Award Agreement (Filed With SEC on December 14, 2020)

Form of Indemnity Agreement (Filed With SEC on November 20, 2020)

Employment Agreement, dated June 1, 2020, by and between the Company and Mack Treece (Filed With SEC on November 20, 2020)

Employment Agreement, dated June 22, 2020, by and between the Company and Joe Mastrangelo (Filed With SEC on November 20, 2020)

B. Riley Principal Merger Corp. II 2020 Incentive Plan (Filed With SEC on November 20, 2020)

Registration Rights Agreement, dated November 16, 2020, by and among the Company and the securityholders party thereto (Filed With SEC on November 20, 2020)

Sponsor Earnout Letter (Filed With SEC on November 20, 2020)

Form of Subscription Agreement (Filed With SEC on November 20, 2020)

Specimen Warrant Certificate (Filed With SEC on November 20, 2020)

Specimen Common Stock Certificate (Filed With SEC on November 20, 2020)

Forward Purchase Agreement, dated May 19, 2020, by and between the Company and B. Riley Principal Investments, LLC (Filed With SEC on May 22, 2020)

Underwriting Agreement, dated May 19, 2020, by and between the Company and B. Riley FBR, Inc., as representative of the several underwriters (Filed With SEC on May 22, 2020)

Business Combination Marketing Agreement, dated May 19, 2020, by and between the Company and B. Riley FBR, Inc (Filed With SEC on May 22, 2020)

Warrant Agreement, dated May 19, 2020, by and between the Company and Continental Stock Transfer & Trust Company, as warrant agent (Filed With SEC on May 22, 2020)

Letter Agreement, dated May 19, 2020, by and among the Company, its officers, its directors and B. Riley Principal Sponsor Co. II, LLC (Filed With SEC on May 22, 2020)

Investment Management Trust Agreement, dated May 19, 2020, by and between the Company and Continental Stock Transfer & Trust Company, as trustee (Filed With SEC on May 22, 2020)

Registration Rights Agreement, dated May 19, 2020, by and between the Company, B. Riley Principal Sponsor Co., LLC and the Companys independent directors (Filed With SEC on May 22, 2020)

Private Placement Units Purchase Agreement, dated May 19, 2020, by and between the Company and B. Riley Principal Sponsor Co., LLC (Filed With SEC on May 22, 2020)

Administrative Support Agreement, dated May 19, 2020, by and among the Company and B. Riley Corporate Services, Inc (Filed With SEC on May 22, 2020)

Form of Underwriting Agreement (Filed With SEC on May 18, 2020)

Form of Warrant Agreement between Continental Stock Transfer & Trust Company, LLC and the Registrant (Filed With SEC on May 18, 2020)

Form of Letter Agreement among the Registrant and our officers, directors and B. Riley Principal Sponsor Co. II, LLC (Filed With SEC on May 18, 2020)

Form of Investment Management Trust Agreement between Continental Stock Transfer & Trust Company, LLC and the Registrant (Filed With SEC on May 18, 2020)

Private Placement Units Purchase Agreement between the Registrant and B. Riley Principal SponsorCo.II,LLC (Filed With SEC on May 18, 2020)

Form of Forward Purchase Agreement (Filed With SEC on May 18, 2020)

Form of Registration Rights Agreement between the Registrant and certain security holders (Filed With SEC on May 18, 2020)

Form of Forward Purchase Agreement (Filed With SEC on May 15, 2020)

Private Placement Units Purchase Agreement between the Registrant and B. Riley Principal SponsorCo.II,LLC (Filed With SEC on May 15, 2020)

Form of Investment Management Trust Agreement between Continental Stock Transfer & Trust Company, LLC and the Registrant (Filed With SEC on May 15, 2020)

Form of Letter Agreement among the Registrant and our officers, directors and B. Riley Principal Sponsor Co. II, LLC (Filed With SEC on May 15, 2020)

Form of Underwriting Agreement (Filed With SEC on May 15, 2020)

Form of Underwriting Agreement (Filed With SEC on May 13, 2020)

Form of Letter Agreement among the Registrant and our officers, directors and B. Riley Principal Sponsor Co. II, LLC (Filed With SEC on May 13, 2020)

Amended and Restated Promissory Note, dated May 12, 2020, issued to Sponsor (Filed With SEC on May 13, 2020)

Private Placement Units Purchase Agreement between the Registrant and B. Riley Principal SponsorCo.II,LLC (Filed With SEC on May 13, 2020)

Form of Forward Purchase Agreement (Filed With SEC on May 13, 2020)

Form of Registration Rights Agreement between the Registrant and certain security holders (Filed With SEC on May 13, 2020)

Form of Business Combination Marketing Agreement between the Registrant and B. Riley FBR, Inc (Filed With SEC on April 28, 2020)

Specimen Unit Certificate (Filed With SEC on April 28, 2020)

Specimen Class A Common Stock Certificate (Filed With SEC on April 28, 2020)

Specimen Warrant Certificate (Filed With SEC on April 28, 2020)

Form of Warrant Agreement between Continental Stock Transfer & Trust Company, LLC and the Registrant (Filed With SEC on April 28, 2020)

Form of Letter Agreement among the Registrant and our officers, directors and B. Riley Principal Sponsor Co. II, LLC (Filed With SEC on April 28, 2020)

Promissory Note, dated February 4, 2020, issued to Sponsor (Filed With SEC on April 28, 2020)

Form of Investment Management Trust Agreement between Continental Stock Transfer & Trust Company, LLC and the Registrant (Filed With SEC on April 28, 2020)

Form of Registration Rights Agreement between the Registrant and certain security holders (Filed With SEC on April 28, 2020)

Private Placement Units Purchase Agreement between the Registrant and B. Riley Principal Sponsor Co. II, LLC (Filed With SEC on April 28, 2020)

Form of Indemnity Agreement (Filed With SEC on April 28, 2020)

Form of Administrative Support Agreement by and between the Registrant and B. Riley Corporate Services, Inc (Filed With SEC on April 28, 2020)

Form of Forward Purchase Agreement (Filed With SEC on April 28, 2020)

Form of Underwriting Agreement (Filed With SEC on April 28, 2020)