A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6145-00-830-8210
NSN 5905-01-459-8151
NSN 5925-01-265-7749
NSN 6240-01-633-9357
NSN 5835-00-454-7239
NSN 6240-01-032-5105
NSN 6150-01-228-6300
NSN 5990-01-117-7932
NSN 6220-01-305-1223
NSN 5915-01-230-5993
NSN 6110-01-415-0589
NSN 5915-01-226-8398