A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5920-01-411-5316
NSN 6610-01-474-8520
NSN 5835-01-416-6455
NSN 4140-00-249-5603
NSN 5920-01-397-1280
NSN 6650-01-554-2824
NSN 5985-01-327-7578
NSN 6610-00-010-9714
NSN 6145-01-285-8953
NSN 5935-01-333-9579
NSN 5915-00-629-4294
NSN 6685-01-106-0962