A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5950-00-533-8057
NSN 5990-01-604-0060
NSN 5965-00-900-8102
NSN 5895-00-269-3848
NSN 7035-01-457-5645
NSN 6240-01-558-8379
NSN 6240-01-394-5320
NSN 5996-01-054-4954
NSN 6110-00-571-1749
NSN 6135-01-576-9616
NSN 5965-00-045-3440
NSN 6620-01-010-0518