A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6105-00-770-5838
NSN 6150-01-408-6209
NSN 5910-00-804-6767
NSN 6320-00-831-2227
NSN 6145-01-335-0088
NSN 5910-01-013-8957
NSN 5855-00-688-9954
NSN 5930-00-517-6249
NSN 5920-00-681-1172
NSN 6645-01-343-1676
NSN 6650-00-393-0447
NSN 5965-00-001-7593