Depressed Center Grinding Wheel Abrasive Material Zirconia Alumina Connector Size 5/8 in Connector Type Unthreaded Hole Grit 24 Overall Diameter 4 in Overall Thickness 0.25 in Primary Material Applicationn Cast Iron Compatible Tool Type Angle Grinder Series BlueFire ZA Wheel Type Type 27 Maximum Operating Speed 15 280 RPM Grade Extra Coarse