The supplier must deliver goods that meet the prescribed physical limitations of the current Postal Service Domestic Mail Manual either by its own personnel/equipment or by use of the Postal Service, unless the CO grants a waiver of this requirement. The reasoning for such waivers must be documented in the contract file. In accordance with paragraph t of Clause 4–1: General Terms and Conditions, the supplier is responsible for ensuring that the packing and packaging are sufficient to protect the goods and ensure usability upon receipt. In addition, Clause 2-9: Definition of Delivery Terms and Supplier’s Responsibilities may be used to define the shipping requirements of the contract.