A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5935-00-686-5909
NSN 5965-00-400-6228
NSN 2925-00-096-5526
NSN 5915-01-565-1807
NSN 6105-01-383-4176
NSN 5855-01-565-3266
NSN 6685-01-495-0350
NSN 5998-01-066-3700
NSN 5950-00-084-2919
NSN 5925-00-205-2767
NSN 6645-00-920-8690
NSN 5855-00-631-4565