Flap Disc, Abrasive Type Coated, Abrasive Material Zirconia Alumina, Grade Extra Coarse, Backing Plate Material Aluminum, Connector Size 5/8 In. -11, Connector Type Threaded Hole, Density Rating Standard, Flap Disc Type Type 29, Overall Diameter 4 1/2 in, Quick Change System Not Applicable, Series Tiger Aluminum Back, Backing Material Aluminum, Grit 36, Maximum Operating Speed 13, 000 RPM