A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6110-01-063-7423
NSN 6240-01-287-4345
NSN 5998-01-455-4518
NSN 5990-01-514-8708
NSN 5985-01-320-5359
NSN 6150-01-400-2552
NSN 5925-01-127-7608
NSN 5910-00-492-4131
NSN 6105-01-460-4280
NSN 5998-01-596-4488
NSN 5985-01-250-1680
NSN 5925-01-279-0011