A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5920-00-280-3182
NSN 5855-01-629-0954
NSN 6150-01-022-1414
NSN 5910-01-350-9449
NSN 6685-00-705-1522
NSN 5915-01-391-7830
NSN 5945-00-990-0283
NSN 5910-01-596-2780
NSN 5905-01-552-3764
NSN 6135-00-134-6648
NSN 5945-01-433-7528
NSN 5998-00-050-3711