A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5990-01-443-2931
NSN 6130-01-266-5943
NSN 6685-01-368-3262
NSN 7035-01-116-6223
NSN 5996-00-633-1177
NSN 5965-01-602-8072
NSN 5925-01-547-4304
NSN 5975-00-009-8718
NSN 6685-01-503-0772
NSN 5950-00-904-6093
NSN 6685-00-816-8838
NSN 4140-00-814-5987