Driver is broached for a .095" keyway and includes a internal hex nut that fastens the driver to all industry standard magnetos.
Racer should check there MBR/Arias drive before purchasing to make sure there mag drive is 9/16" hex.
Can also be used to drive a magneto off a Enderle dual fuel pump drive. Mag driver is made from durable heat treated steel and black oxide coated for a superior finish.