A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6150-00-712-0256
NSN 5965-01-051-3727
NSN 4140-00-133-7986
NSN 2925-00-555-8836
NSN 5945-01-141-7497
NSN 6130-01-233-7141
NSN 6320-01-651-7476
NSN 5925-00-999-9320
NSN 5935-01-546-2451
NSN 5915-01-476-9388
NSN 5895-00-488-6248
NSN 5965-01-237-3342