A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6240-00-397-3864
NSN 5910-00-482-1933
NSN 6130-01-151-0901
NSN 5925-01-359-4080
NSN 6145-01-412-7517
NSN 2925-01-052-0636
NSN 5996-01-069-2370
NSN 5960-01-117-1887
NSN 5998-00-925-9927
NSN 5998-00-882-8838
NSN 5935-01-265-6893
NSN 5925-01-486-6760