A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5930-01-056-6680
NSN 6320-00-925-0558
NSN 5990-00-105-7831
NSN 6610-01-193-2169
NSN 5975-00-990-7024
NSN 5975-00-665-3644
NSN 5935-00-410-5402
NSN 5985-00-181-3860
NSN 5985-01-272-9623
NSN 6645-00-888-5820
NSN 5855-01-505-5144
NSN 6110-01-426-1790