15.9 ounces is maximum weight of an individual piece.
Mail needs to be determined by using template if it is classified as a letter size or flat size.
C. Must have a postage slip completed with number of pieces, department name, account number, and signature. D. Packages must be tied securely using two strong, thick rubber bands. All pieces in a package must be faced in the same direction with an address visible on the top piece. Only one pressure sensitive label on top piece of each package located in lower left corner. H. Address block must have a complete ZIP Code and should follow the new postal guidelines for addressing.