A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5925-01-476-8727
NSN 5930-01-381-1059
NSN 5855-00-821-7512
NSN 6150-01-104-9011
NSN 5998-00-372-6047
NSN 6130-01-279-8297
NSN 5950-00-455-8564
NSN 6135-00-809-2148
NSN 5925-01-382-9313
NSN 2925-00-480-9068
NSN 5935-01-229-5419
NSN 6145-01-529-6566