The size of the box must be adequate to contain the items and provide enough space for cushioning material. For Registered mail containers must be sealed with paper tape. Tape must visibly damage the envelope or wrapper if removed and must absorb the ink in a postmark impression. Express Mail is the highest priority in handling and the most highly reliable service. The two to three day delivery of Express mail exceeds the needs of most military administrative material.
Express mail provides shipment of letters, documents, and other mailed items.
Express mail collected during the day will be processed the same day. On days before weekends or holidays unless the sender has verified that someone will be available to accept it and work on it during the weekend or holiday. This is the most expensive service. Priority Mail is used when the speed of express mail is not needed, but preferential handling is desired. Priority mail offers faster delivery at a less expensive rate.