; (B) to return to the Secretary any amount of the grant that is— (i) not used by the grant recipient for the purpose for which the grant was awarded; or (ii) not obligated or expended within the timeframe provided in the agreement; (C) to maintain such records as the Secretary may require and make such records available for review and audit by the Secretary; and (D) not to purchase any product or material for the project or program using grant funds, including any commercially available off-the-shelf item, unless such product or material is— (i) an unmanufactured article, material, or supply that has been mined or produced in the United States; or (ii) a manufactured article, material, or supply that has been manufactured in the United States substantially all from articles, materials, or supplies mined, produced, or manufactured in the United States. (c) Guidelines The Secretary shall issue guidelines to establish appropriate accounting, reporting, and review procedures to ensure that— (1) amounts awarded as grants under this section are used for the purposes for which such amounts were made available; and (2) an entity that receives a grant under this section complies with the terms of the agreement such entity enters into with the Secretary pursuant to subsection (b)(3). (d) Definitions In this section: (1) The term commercially available off-the-shelf item — (A) means any item of supply (including construction material) that is— (i) a commercial item, as defined by section 2.101 of title 48, Code of Federal Regulations (as in effect on the date of the enactment of the National Defense Authorization Act for Fiscal Year 2024); and (ii) sold in substantial quantities in the commercial marketplace