As prescribed in 16.603-4(b)(1), insert the following clause in solicitations and contracts when a letter contract is contemplated, except that it may be omitted from letter contracts awarded on SF 26:
The Contractor shall indicate acceptance of this letter contract by signing three copies of the contract and returning them to the Contracting Officer not later than ___ [insert date]. Upon acceptance by both parties, the Contractor shall proceed with performance of the work, including purchase of necessary materials.
(End of clause)