Flap Disc, Abrasive Type Coated, Abrasive Material Zirconia Alumina, Grade Extra Coarse, Backing Plate Material Fiberglass, Connector Size 7/8 in, Connector Type Unthreaded Hole, Density Rating High, Flap Disc Type Type 27, Overall Diameter 4 1/2 in, Series 577F, Backing Material Polyester, Backing Weight YF, Coating Coverage Closed, Grit 36, Maximum Operating Speed 13,300 RPM, Color Green, Features Performance Coated