A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5975-00-248-2560
NSN 5998-01-047-3175
NSN 5905-01-177-1661
NSN 5985-00-400-5946
NSN 6685-01-121-0572
NSN 6105-01-319-3984
NSN 4140-01-294-4044
NSN 5998-01-513-9898
NSN 4140-01-065-1884
NSN 5925-00-188-8678
NSN 6320-00-004-9158
NSN 6135-01-387-0754