This attachment uses an 8″ contact wheel which makes the attachment more compact. The 8″ wheel also produces a significantly higher belt speed, in the same way the expander wheels do, and fit any 1/2 hp or larger grinder with a shaft at least 2-1/2″ long and 5/8″ in diameter. We also stock a left hand version. We have a wide range of 2×48″ belts that fit this unit.