MIL-PRF-38169A, PERFORMANCE SPECIFICATION: LENS, GOGGLE AND VISOR, HELMET, OPTICAL CHARACTERISTICS, GENERAL SPECIFICATION FOR (10 JUN 1998) [SUPERSEDING MIL-L-38169]

MIL-PRF-38169A, PERFORMANCE SPECIFICATION: LENS, GOGGLE AND VISOR, HELMET, OPTICAL CHARACTERISTICS, GENERAL SPECIFICATION FOR (10 JUN 1998) [SUPERSEDING MIL-L-38169]., This is a general specification for optical characteristics of helmet visor and goggle lenses.