A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6645-01-383-1083
NSN 6240-01-294-6469
NSN 6610-01-224-7247
NSN 5998-01-400-1120
NSN 5935-01-286-0630
NSN 5910-01-597-5082
NSN 5920-00-827-4390
NSN 6105-01-528-8027
NSN 6620-00-684-6771
NSN 5835-00-275-0584
NSN 6150-01-430-3902
NSN 5945-01-647-0755