A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6685-00-881-3063
NSN 6320-01-425-1417
NSN 4140-00-242-6465
NSN 5999-01-261-6757
NSN 5915-00-654-5794
NSN 5965-01-360-6568
NSN 6610-00-704-3070
NSN 5910-01-129-4458
NSN 6220-01-006-9398
NSN 5950-01-109-5286
NSN 5965-01-449-1101
NSN 5965-01-505-3716