Flap Disc Abrasive Type Coated Abrasive Material Zirconia Alumina Grade Coarse Backing Plate Material Fiberglass Connector Size 5/8 In.-11 Connector Type Threaded Hole Density Rating Standard Flap Disc Type Radial Overall Diameter 4 1/2 in Series Z SGP CURVE Backing Material Fiberglass Backing Weight Consumable Grit 40 Maximum Operating Speed 13 300 RPM