A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5915-01-578-7264
NSN 6145-01-286-8888
NSN 6135-01-658-3265
NSN 5905-00-983-2437
NSN 6650-01-424-8048
NSN 5935-00-571-1413
NSN 5990-00-239-3432
NSN 5935-01-474-6361
NSN 4140-00-076-4088
NSN 5855-01-334-6594
NSN 6645-01-493-2620
NSN 6620-01-572-4486