-Off & Grinding Wheel, Abrasive Material Zirconia Alumina/Silicon Carbide, Connector Size 7/8 in, Connector Type Unthreaded Hole, Grit 24, Overall Diameter 4 1/2 in, Overall Thickness 0.125 in, Primary Material Applicationn Cast Iron, Compatible Tool Type Angle Grinder, Series BlueFire ZC, Wheel Type Type 27, Maximum Operating Speed 13,580 RPM, Grade Extra Coarse