A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5935-00-952-2204
NSN 5905-01-098-4821
NSN 6145-00-493-4073
NSN 5960-01-048-8228
NSN 6145-00-173-5177
NSN 5999-01-250-3487
NSN 5835-00-898-0201
NSN 6105-01-533-3411
NSN 5855-01-544-4277
NSN 2925-01-219-9471
NSN 6110-00-480-4827
NSN 6105-01-166-4923