Home > About USPS & News > Forms & Publications > Postal Periodicals and Publications > Publications > Publication 401 - Guide to Manifest Mailing System > 6 Batch Manifest > 6-3 Keyline Location
6-3.1 The keyline must be readily identifiable.
6-3.2 The keyline must be placed on the address side anywhere that does not conflict with other postal requirements.
6-3.3 Keylines printed on inserts in window envelopes must be entirely visible with at least 1/8-inch clearance between the keyline and the edge of the window.