DMM TOC > 100 Retail Letters, Cards, Flats, and Parcels > 180 Library Mail|
The mailer is responsible for proper postage payment. Subject to the corresponding standards, postage for Library Mail may be paid by any method (see 604) except precanceled stamps. Pieces with postage affixed must bear the correct postage. Permit imprint may be used for mailings that contain nonidentical-weight pieces only under 705, Advanced Preparation and Special Postage Payment Systems. Identical-weight permit imprint mail also may be mailed under 705.
A mailer may be authorized to mail material without affixing postage when payment is made at the time of mailing from a permit imprint advance deposit account established with the USPS for that purpose. This payment method may be used for postage and extra service fees and must not be used to pay postage on any mailpiece that is designed for reply mail purposes.
Permit imprint mailings must contain at least 200 pieces or 50 pounds, except in the case of single-piece mailings submitted under the terms of an approved manifest mailing system agreement with a minimum volume reduction provision.