This attachment uses an 8" contact wheel. The 8" wheel produces a significantly higher belt speed than most grinder attachements, 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 2x36 belts that fits this unit. Baldor 1/2hp or 3/4hp grinder 3600rpm motor is recommended.