A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5998-00-633-5169
NSN 5960-00-974-4003
NSN 5985-01-412-1375
NSN 6610-01-390-6925
NSN 6220-00-862-2771
NSN 2925-01-329-3665
NSN 6645-01-633-1852
NSN 5855-00-051-2792
NSN 6130-00-917-5198
NSN 5950-01-098-3858
NSN 5910-00-058-9610
NSN 6145-01-381-1303