DMM TOC > 100 Retail Letters, Cards, Flats, and Parcels > 130 First Class Mail|
135 Mail Preparation
1.0 Preparation for First-Class Mail
a. Each piece must have a delivery address but is not required to bear the marking “First-Class” or “First-Class Mail.”
b. There are no sorting requirements for single-piece First-Class Mail, but five or more letter-size pieces bearing metered postage and all pieces bearing permit imprints must be faced with the addresses in one direction and bundled. Bundling of letter-size pieces is not required if they fill a letter tray. Metered mail and permit imprint mail may not be bundled or trayed together.