A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 4140-01-026-1381
NSN 6130-01-487-3637
NSN 5935-01-649-9182
NSN 6650-00-445-6990
NSN 5905-01-624-2011
NSN 5905-00-454-8310
NSN 5999-00-021-2327
NSN 5895-01-367-0447
NSN 6685-01-461-4054
NSN 5965-01-323-0501
NSN 6685-00-413-6671
NSN 6220-00-247-4859