39 U.S. Code § 3404 - Unsealed letters sent by blind or physically handicapped persons

Unsealed letters sent by a blind person or a person having a physical impairment, as described in section 3403(a)(1) of this title, in raised characters or sightsaving type, or in the form of sound recordings, may be mailed free of postage.

(Pub. L. 91–375, Aug. 12, 1970, 84 Stat. 758.)
Effective Date

Section effective July 1, 1971, pursuant to Resolution No. 71–9 of the Board of Governors. See section 15(a) of Pub. L. 91–375, set out as a note preceding section 101 of this title.