A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6610-01-459-8722
NSN 6220-00-625-3915
NSN 6220-00-188-7525
NSN 5985-01-544-0129
NSN 5985-01-126-2687
NSN 5905-00-170-8370
NSN 6130-00-862-7093
NSN 6135-01-100-3593
NSN 6240-00-383-7668
NSN 6645-01-025-1002
NSN 7035-01-413-6697
NSN 6650-01-468-4681