Colo. Rev. Stat. § 4-2-507
tion. (1) Tender of delivery is a condition to the buyer's duty to accept the goods and, unless otherwise agreed, to his duty to pay for them. Tender entitles the seller to acceptance of the goods and to payment according to the contract.
Source: L. 65: p. 1324, § 1. C.R.S. 1963: § 155-2-507.