A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6150-01-089-6764
NSN 5915-00-294-9419
NSN 5935-01-183-6499
NSN 5935-01-476-7456
NSN 5925-00-269-2178
NSN 5910-00-937-8941
NSN 6130-01-326-8696
NSN 5915-01-360-0677
NSN 5925-01-356-7571
NSN 5945-01-014-4114
NSN 6320-01-202-8761
NSN 6240-01-258-6298