A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5990-01-306-9290
NSN 5996-01-627-3817
NSN 5915-00-111-0521
NSN 5835-01-137-6075
NSN 5985-01-448-9550
NSN 5835-01-031-7265
NSN 6130-01-628-7106
NSN 6320-01-441-2438
NSN 5990-01-143-2518
NSN 5895-00-358-1922
NSN 7035-01-138-5781
NSN 5996-01-445-8522