A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5950-01-180-4032
NSN 6110-01-145-5991
NSN 5935-01-571-7071
NSN 6685-01-235-9173
NSN 4140-00-459-9045
NSN 6220-01-071-9428
NSN 5960-00-994-4452
NSN 5835-01-246-0972
NSN 5905-01-249-0299
NSN 6320-00-456-0836
NSN 5960-01-160-2440
NSN 5960-00-497-9862