Depressed Center Grinding Wheel Abrasive Material Zirconia Alumina/Silicon Carbide Connector Size 5/8 In.-11 Connector Type Threaded Hole Grit 24 Overall Diameter 9 in Overall Thickness 0.25 in Primary Material Applicationn Cast Iron Compatible Tool Type Angle Grinder Series BlueFire ZC Wheel Type Type 27 Maximum Operating Speed 6 600 RPM Grade Extra Coarse