Flap Disc Abrasive Type Coated Abrasive Material Zirconia Alumina Grade Fine 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 Ovation Backing Material Fiberglass Backing Weight H Grit 120 Maximum Operating Speed 13 300 RPM