MIL-L-50064C, MILITARY SPECIFICATION: LENS, OPHTHALMIC, SIMPLE (FOR ABC-M17 MASK) (30-SEP-1964) [CANCELLED W/ NO S/S DOCUMENT]
MIL-L-50064C, MILITARY SPECIFICATION: LENS, OPHTHALMIC, SIMPLE (FOR ABC-M17 MASK) (30-SEP-1964) [CANCELLED W/ NO S/S DOCUMENT]., This specification covers two types of cast, cylindrical plastic lenses.