Flap Disc Abrasive Type Coated Abrasive Material Ceramic Grade Coarse Backing Plate Material Fiberglass Connector Size 5/8 In.-11 Connector Type Threaded Hole Flap Disc Type Type 29 Overall Diameter 4 1/2 in Series Apex Backing Material Polyester Backing Weight Y Grit 40 Maximum Operating Speed 13 300 RPM Features Hard Edge