A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5925-01-408-0632
NSN 5996-01-380-9484
NSN 6135-00-305-2052
NSN 5960-00-584-4553
NSN 6145-01-450-8419
NSN 6105-01-246-0008
NSN 5925-00-757-2947
NSN 5930-01-482-1247
NSN 5855-01-454-0704
NSN 2925-00-717-5430
NSN 6610-00-536-4977
NSN 6130-00-747-9714