A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5920-01-449-2172
NSN 5998-01-225-5167
NSN 6685-00-246-5349
NSN 5999-01-293-1575
NSN 5945-01-443-2469
NSN 5920-01-437-9312
NSN 5930-00-820-9546
NSN 5975-01-081-1074
NSN 5915-00-155-4766
NSN 5950-00-529-0264
NSN 6130-01-561-4638
NSN 6110-00-363-3974