(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.
(
Section effective July 1, 1971, pursuant to Resolution No. 71–9 of the Board of Governors. See section 15(a) of