A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-01-388-3735
NSN 5998-01-395-6642
NSN 5950-00-670-7842
NSN 5975-00-894-9639
NSN 6220-01-566-1982
NSN 5920-01-449-2172
NSN 5855-00-156-5489
NSN 6110-01-542-1248
NSN 5998-01-161-8568
NSN 5999-01-652-6671
NSN 5910-01-235-4086
NSN 5945-01-315-4424