A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5895-00-556-9162
NSN 5985-00-283-6220
NSN 5925-01-050-8410
NSN 5905-01-203-9330
NSN 4140-01-139-0141
NSN 5960-01-468-6508
NSN 6685-00-247-8703
NSN 5930-01-220-6074
NSN 5905-00-156-7154
NSN 6685-00-862-5431
NSN 6240-00-722-0268
NSN 6130-01-262-2708