A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5999-01-240-2204
NSN 6685-01-219-6623
NSN 5999-01-029-2375
NSN 5910-00-055-1746
NSN 6620-01-183-1900
NSN 2925-00-373-8837
NSN 6105-01-057-4620
NSN 6320-01-046-5228
NSN 6610-01-470-3413
NSN 6620-00-909-3984
NSN 6135-01-164-3561
NSN 5960-00-882-4424