A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5950-01-378-3907
NSN 5999-01-019-7463
NSN 6240-01-461-8193
NSN 6130-00-977-4279
NSN 5905-00-466-1251
NSN 5975-01-212-2020
NSN 6650-01-353-7809
NSN 5998-00-460-5134
NSN 7035-00-238-3662
NSN 5930-00-518-0872
NSN 5930-01-329-7952
NSN 5925-01-398-0517