Unitized Non-Woven Wheels, Abrasive Material Aluminum Oxide, Density Rating Medium (6), Grade Medium, Series ZWEB, Face Width 1/4 in, Maximum Operating Speed 6,000 RPM, Overall Diameter 6 in, Connector Size 1 in, Connector Type Unthreaded Hole, Quick Change System Not Applicable, Abrasive Type Non-Woven, Grit Not Applicable.