(a) The matter described in subsection (b) of this section (other than matter mailed under section 3404 of this title ) may be mailed free of postage, if— (1) the matter is for the use of the blind or other persons who cannot use or read conventionally printed material because of a physical impairment and who are certified by competent authority as unable to read normal reading material in accordance with the provisions of sections 135a and 135b of title 2; (2) no charge, or rental, subscription, or other fee, is required for such matter or a charge, or rental, subscription, or other fee is required for such matter not in excess of the cost thereof; (3) the matter may be opened by the Postal Service for inspection; and (4) the matter contains no advertising. (b) The free mailing privilege provided by subsection (a) of this section is extended to— (1) reading matter and musical scores; (2) sound reproductions; (3) paper, records, tapes, and other material for the production of reading matter, musical scores, or sound reproductions; (4) reproducers or parts thereof, for sound reproductions; and (5) braille writers, typewriters, educational or other materials or devices, or parts thereof, used for writing by, or specifically designed or adapted for use of, a blind person or a person having a physical impairment as described in subsection (a)(1) of this section. ( Pub. L. 91–375 , Aug. 12, 1970 , 84 Stat. 757 .) Statutory Notes and Related Subsidiaries 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 . CFR Title Parts 39 20 , 111 , 113 , 255