A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6135-01-265-1384
NSN 5945-01-028-6989
NSN 5925-01-522-0439
NSN 6320-01-300-7994
NSN 6135-01-286-9563
NSN 5930-00-012-3200
NSN 5965-01-243-5494
NSN 5996-01-119-9660
NSN 5990-01-268-6767
NSN 6620-01-042-2046
NSN 6650-00-526-7785
NSN 5915-00-925-0835