A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6650-01-271-2960
NSN 6135-01-512-8740
NSN 6610-01-237-5815
NSN 6610-01-125-5761
NSN 5930-01-316-7681
NSN 6130-01-265-2767
NSN 5960-01-013-9346
NSN 2925-01-483-2389
NSN 5998-01-514-0376
NSN 5945-01-243-0893
NSN 6240-01-167-5040
NSN 6650-01-423-9772