A contract is an agreement by which two parties mutually promise to buy or sell some products. In practice, some informal contracts may be reached orally. This is understandable, but may lead to unfortunate consequences. A reasonable exporter should at least insist on strict observance of the legal requirements in case of orders that are not routine transactions. When the goods ordered represent a considerable value, a formal contract embodying all terms of the agreement should be prepared in duplicate; each copy should be signed by both parties, and each party should retain a copy of the contract.