A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5960-01-336-4239
NSN 6240-00-299-9819
NSN 6110-01-369-5561
NSN 4140-01-634-0330
NSN 6620-01-633-8443
NSN 5895-01-571-6249
NSN 5925-01-303-8381
NSN 5985-00-106-9256
NSN 6620-01-385-6172
NSN 6320-01-429-9871
NSN 6650-01-235-0981
NSN 6650-01-168-8451