Due to the long-throw articulation of the G15 and G21 we could not integrate fan cooling into their counterbalance. So we engineered these long-throw machines with their cooling fan integrated into the backing plate. These plates are precision balanced and weight-matched to the G15 and G21 counterbalance and our BOSS lineup of pads. This 6" plate is a replacement for the G21 and allows the G15 to be converted to our 6" pad system. Includes black-, silver-, and copper-colored fasteners.