Flap Disc Abrasive Type Coated Abrasive Material Zirconia Alumina Grade Medium Backing Plate Material Fiberglass Connector Size 5/8 In.-11 Connector Type Threaded Hole Density Rating Standard Flap Disc Type Type 29 Overall Diameter 4 1/2 in Series Gemini R766 Backing Material Cotton Backing Weight X Coating Coverage Semi-Open Grit P120 Maximum Operating Speed 13 300 RPM Color Black