Leighton Industries needed steel pipe to build furnaces for a customer. Leighton sent Callier Steel an order for a certain quantity of “A 106 Grade B” steel. Callier confirmed the order and created a contract by sending an invoice to Leighton, stating that it would send “A 106 Grade B” steel, as ordered. Callier delivered the steel, and Leighton built the furnaces, but they leaked badly and required rebuilding. Tests demonstrated that the steel was not in fact “A 106 Grade B,” but an inferior steel. Leighton sued. Who wins?