A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6240-01-496-3847
NSN 5855-01-480-4876
NSN 6650-00-958-7408
NSN 6150-01-257-6656
NSN 5960-01-344-2604
NSN 5960-01-009-2899
NSN 5965-01-431-5809
NSN 5915-01-364-7917
NSN 5999-00-459-1211
NSN 6240-00-166-2271
NSN 5990-00-965-0495
NSN 5945-01-630-6732