Non-Woven Depressed Center Disc, Abrasive Material Aluminum Oxide, Grade Extra Coarse, Overall Diameter 4 1/2 in, Series XC-DC, Maximum Operating Speed 13,300 RPM, Connector Size 7/8 in, Connector Type Unthreaded Hole, Abrasive Type Non-Woven, Backing Material Nylon Mesh, Color Green, Disc Shape Type Type 27