A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5996-00-636-4849
NSN 5996-01-267-2791
NSN 5925-00-188-8678
NSN 5930-01-528-6757
NSN 5990-01-507-7495
NSN 6145-00-152-9954
NSN 5915-00-909-9522
NSN 5950-00-246-6362
NSN 6320-00-308-7386
NSN 6105-00-556-6333
NSN 6150-01-395-7422
NSN 4140-01-175-7081