A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5996-01-271-9927
NSN 5835-01-527-2629
NSN 5965-00-080-2045
NSN 5965-00-015-3660
NSN 5855-01-492-5666
NSN 5990-01-609-4793
NSN 5985-01-386-3701
NSN 6240-01-298-0470
NSN 5930-01-538-8803
NSN 6650-00-012-2430
NSN 5975-01-123-9111
NSN 5985-01-148-4178