A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6135-00-789-2865
NSN 7035-01-466-1577
NSN 5990-01-338-2103
NSN 6110-00-518-2998
NSN 5895-00-997-4995
NSN 6145-00-504-5221
NSN 2925-01-629-9416
NSN 4140-00-334-4762
NSN 4140-01-147-4764
NSN 5996-01-502-2907
NSN 5915-00-009-9975
NSN 5996-01-400-0917