Surface-Conditioning Disc Abrasive Material Ceramic Grade Medium Overall Diameter 4 1/2 in Series Rapid Prep XHD Maximum Operating Speed 12 000 RPM Connector Size 7/8 in Connector Type Unthreaded Hole Abrasive Type Non-Woven Backing Material Fiber Backing Weight Not Applicable Color Maroon Grit 100 Resistance Properties Smear Wear