MS51021C, MILITARY STANDARD: SETSCREW-HEXAGON SOCKET, CUP POINT, CORROSION RESISTING (CHROME-NICKEL) STEEL, PASSIVATED, UNC-3A PLAIN AND SELF LOCKING (29-DEC-1972) [SUPERSEDED BY NASM51021]

MS51021C, MILITARY STANDARD: SETSCREW-HEXAGON SOCKET, CUP POINT, CORROSION RESISTING (CHROME-NICKEL) STEEL, PASSIVATED, UNC-3A PLAIN AND SELF LOCKING (29-DEC-1972) [SUPERSEDED BY NASM51021].