400.2-311. (1) An agreement for sale which is otherwisesufficiently definite (subsection (3) of section 400.2-204) to bea contract is not made invalid by the fact that it leavesparticulars of performance to be specified by one of the parties.Any such specification must be made in good faith and withinlimits set by commercial reasonableness.
(2) Unless otherwise agreed specifications relating toassortment of the goods are at the buyer's option and except asotherwise provided in subsections (1)(c) and (3) of section400.2-319 specifications or arrangements relating to shipment areat the seller's option.
(3) Where such specification would materially affect theother party's performance but is not seasonably made or where oneparty's cooperation is necessary to the agreed performance of theother but is not seasonably forthcoming, the other party inaddition to all other remedies
(a) is excused for any resulting delay in his ownperformance; and
(b) may also either proceed to perform in any reasonablemanner or after the time for a material part of his ownperformance treat the failure to specify or to cooperate as abreach by failure to deliver or accept the goods.
(L. 1963 p. 503 ยง 2-311)