Maximum weight is 70 lbs. Delivery zones and shipping weights determine the postage price. First-Class Mail is the basic postal service mail class for business mail. This would include bills, invoices, checks, letters containing personalized information, and anything sealed against postal inspection. It is not necessary to identify service class on the piece.
Delivery ranges from one to seven days depending on travel distance.
Maximum weight is 13 oz. Parcel Post is generally used by businesses for shipping merchandise. Minimum weight is 1 lb., and maximum weight is 70 lbs. Parcel Post has lower rates and slower travel time than Priority Mail. Delivery ranges from several days to two weeks depending on distance.