Surface-Conditioning Disc Abrasive Material Aluminum Oxide Grade Very Fine Overall Diameter 4 1/2 in Series Vortex Rapid Prep Maximum Operating Speed 11 000 RPM Connector Size 7/8 in Connector Type Unthreaded Hole Abrasive Type Non-Woven Backing Material Fiber Backing Weight X Color Blue Grit 180-360 Package Quantity 25