A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6620-00-933-1276
NSN 5920-00-681-6464
NSN 6320-00-646-3311
NSN 6105-01-149-2852
NSN 6130-01-160-1727
NSN 6135-01-502-5787
NSN 5960-00-121-1849
NSN 5930-01-421-2715
NSN 6240-01-068-3491
NSN 5935-00-063-9571
NSN 6650-00-500-6455
NSN 5950-00-518-3402