A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5950-00-526-0658
NSN 2925-00-951-0150
NSN 5920-01-183-7938
NSN 6650-00-269-5000
NSN 2925-01-280-1911
NSN 6145-01-628-6616
NSN 6145-00-269-4271
NSN 6620-01-533-5023
NSN 5920-00-842-0236
NSN 6685-00-489-0790
NSN 6610-00-152-7216
NSN 6110-01-601-4048