Unascertained goods may form the subject matter of a valid contract of sale.

He must comply with all the requirements of a valid contract.

The plaintiff sued to enforce the promise, but the court did not find a valid contract.

As only one player had a valid contract for the new league, the club was forced to bring in a large number of new players.

For the program to become available, customers must have a valid contract and must purchase a new phone, rather than simply receive credit to be used at a later date.