A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5915-00-139-6710
NSN 5895-00-752-6171
NSN 5960-00-086-4882
NSN 6145-01-181-2808
NSN 5905-00-256-2169
NSN 5985-00-458-8389
NSN 5996-01-272-2737
NSN 6620-00-140-8644
NSN 6240-01-552-2232
NSN 6105-01-252-6714
NSN 6135-00-840-6451
NSN 5915-01-359-4847