A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-01-470-8625
NSN 5945-00-153-4655
NSN 6130-00-209-6716
NSN 6220-01-634-0660
NSN 6110-01-207-2748
NSN 6130-01-223-6139
NSN 6130-01-487-3758
NSN 5985-01-184-9475
NSN 5975-00-916-9140
NSN 6320-00-284-1524
NSN 5985-01-495-4094
NSN 5985-00-226-6846