A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 7035-00-286-6221
NSN 5990-00-099-0822
NSN 6220-01-273-0934
NSN 6620-00-234-3369
NSN 6130-01-494-6785
NSN 5998-00-988-5298
NSN 2925-01-100-3694
NSN 6220-00-284-3220
NSN 6320-00-270-8222
NSN 5915-00-568-2815
NSN 5996-01-455-2198
NSN 5999-01-482-2975