A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5975-00-387-6515
NSN 6320-01-564-0893
NSN 5930-01-632-1747
NSN 5920-00-133-3931
NSN 5835-01-174-7700
NSN 6320-00-070-4544
NSN 6645-01-168-8465
NSN 6610-00-197-7648
NSN 6150-01-551-1266
NSN 5935-00-294-3330
NSN 5835-01-654-1251
NSN 5910-01-161-0355