Buffing Wheel Mandrel, Abrasive Mounting Connector Size 3/8 in, Abrasive Mounting Connector Type Unthreaded Hole, Tool Mounting Connector Size 1/4 in, Tool Mounting Connector Type Straight Shank, Overall Length 2 1/8 in, Product Type Buffing Wheel Mandrel, Compatible Wheel Diameter (Maximum) 4 in, Compatible Wheel Diameter (Minimum) 3 in, Compatible Wheel Thickness (Maximum) 5/16 in, Maximum Operating Speed 20,000 RPM