Large packaging code designations consist of: two numerals specified in paragraph (a) of this section; followed by the capital letter(s) specified in paragraph (b) of this section.
(a) Large packaging code number designations are as follows: 50 for rigid Large Packagings; or 51 for flexible Large Packagings.
(b) Large Packagings code letter designations are as follows:
(1) “A” means steel (all types and surface treatments).
(2) “B” means aluminum.
(3) “C” means natural wood.
(4) “D” means plywood.
(5) “F” means reconstituted wood.
(6) “G” means fiberboard.
(7) “H” means plastic.
(8) “M” means paper, multiwall.
(9) “N” means metal (other than steel or aluminum).