A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6240-00-218-1480
NSN 5905-00-277-7439
NSN 6130-00-879-3158
NSN 5915-00-151-7849
NSN 6105-01-195-8225
NSN 5975-00-207-3416
NSN 6610-00-097-0180
NSN 5996-01-627-7593
NSN 5925-01-316-4986
NSN 6240-01-421-9388
NSN 6650-01-461-8283
NSN 5960-01-231-9119