A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5930-00-358-6171
NSN 5920-01-454-5147
NSN 4140-01-531-3080
NSN 5855-01-088-4699
NSN 6645-00-812-5243
NSN 5910-00-432-9212
NSN 5910-01-146-4317
NSN 5985-01-265-7024
NSN 6130-01-302-2820
NSN 5960-00-372-4876
NSN 6650-00-202-4540
NSN 6220-01-050-8706