MS20066A, MILITARY STANDARD: KEY, MACHINE, SQUARE IN CROSS-SECTION, BOTH ENDS SQUARE (13 NOV 1964) [SUPERSEDED BY NASM20066]
MS20066A, MILITARY STANDARD: KEY, MACHINE, SQUARE IN CROSS-SECTION, BOTH ENDS SQUARE (13 NOV 1964) [SUPERSEDED BY NASM20066].