A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5915-00-203-5860
NSN 6220-00-520-0333
NSN 5920-01-221-6905
NSN 5990-01-517-7848
NSN 5925-00-284-3726
NSN 5925-01-159-9505
NSN 5998-01-068-3744
NSN 5950-01-454-8689
NSN 5945-01-359-1974
NSN 6130-01-315-3319
NSN 6105-00-862-5788
NSN 6105-01-024-4700