A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6685-00-527-9489
NSN 2925-01-078-7854
NSN 5930-00-880-7131
NSN 6645-00-881-9978
NSN 5915-01-329-8717
NSN 5945-01-487-4127
NSN 6240-01-621-2774
NSN 5935-01-581-2555
NSN 7035-01-361-8821
NSN 5930-00-842-0609
NSN 4140-01-373-7044
NSN 6220-00-366-1670