A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5855-01-162-5251
NSN 5915-01-157-8407
NSN 5996-01-026-9761
NSN 5999-01-502-6031
NSN 5996-01-145-4900
NSN 6320-01-345-5818
NSN 5999-01-006-0375
NSN 5945-01-227-2148
NSN 5855-01-284-3500
NSN 6240-01-152-2662
NSN 6240-01-391-5373
NSN 5925-01-322-3882