A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6240-00-829-4179
NSN 5975-00-157-9676
NSN 5998-01-274-5283
NSN 6135-01-074-8220
NSN 6220-00-909-4385
NSN 7035-01-026-6602
NSN 6105-00-081-9742
NSN 5895-01-573-7270
NSN 5975-01-175-2057
NSN 6620-00-887-8908
NSN 5905-00-216-8671
NSN 5920-01-348-2234