A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5950-01-573-5081
NSN 5998-00-233-6401
NSN 5996-00-404-6704
NSN 5930-00-212-8866
NSN 5935-01-459-7950
NSN 5960-01-347-0751
NSN 6610-01-633-4179
NSN 6110-01-367-6526
NSN 5985-00-113-5058
NSN 5925-00-923-4268
NSN 6320-01-019-1028
NSN 6220-01-584-9421