A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 7035-00-286-6221
NSN 6135-00-087-5300
NSN 5945-00-862-9965
NSN 5998-00-017-4694
NSN 6320-01-369-5014
NSN 5945-00-222-7503
NSN 5925-01-429-0392
NSN 4140-01-283-2287
NSN 5985-01-493-4085
NSN 5996-01-476-7550
NSN 6610-00-804-6312
NSN 5975-01-478-6166