A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6150-01-050-8268
NSN 5965-01-430-4654
NSN 6220-00-810-9563
NSN 5998-01-086-3548
NSN 5945-00-225-6680
NSN 5930-00-955-5705
NSN 5930-00-824-3710
NSN 5905-01-096-5940
NSN 5895-00-280-7528
NSN 5915-01-124-5422
NSN 5950-01-464-6967
NSN 6110-00-271-9928