A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5998-00-731-7155
NSN 5960-01-395-9834
NSN 5920-01-003-2906
NSN 5965-01-600-5604
NSN 7035-01-602-7966
NSN 6220-00-165-7095
NSN 5945-01-498-6410
NSN 6130-00-776-6081
NSN 6150-00-446-7206
NSN 4140-00-118-1816
NSN 5855-01-566-1568
NSN 5975-01-353-8395