A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 7035-00-529-3128
NSN 6135-01-360-9666
NSN 5999-01-140-3829
NSN 6320-00-977-3930
NSN 5945-01-025-0504
NSN 6110-01-522-2781
NSN 5996-01-312-0790
NSN 5920-01-341-3941
NSN 5960-00-536-1535
NSN 5925-00-759-0925
NSN 5915-01-437-4470
NSN 6110-01-213-4973