A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5950-01-273-4273
NSN 5935-01-247-5348
NSN 5905-01-448-9664
NSN 5920-00-241-3838
NSN 5920-01-530-3751
NSN 6320-00-905-0543
NSN 4140-00-892-5952
NSN 6135-01-315-4328
NSN 5905-01-429-9943
NSN 6145-01-445-7942
NSN 6150-01-460-2702
NSN 6220-01-047-7046