A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6110-01-555-7446
NSN 6240-01-200-3453
NSN 6145-00-178-8830
NSN 6240-01-123-8822
NSN 6110-01-432-4517
NSN 5915-00-817-4504
NSN 5998-01-095-8632
NSN 6145-00-286-9588
NSN 5945-01-151-5893
NSN 6130-01-578-8453
NSN 5985-01-255-1154
NSN 4140-00-648-3303