§ 4453. Permissible marks and enclosures Only marks and enclosures permissible in the case of fourth class mail, pursuant to section 4555 of this title, may be placed on or enclosed in third class mail.
Pub. L. 86-682, tit. 39, pt. IV, ch. 65, sec. 4453: Permissible marks and enclosures | Justis AI