-Off & Grinding Wheel, Abrasive Material Zirconia Alumina, Connector Size 3/8 in, Connector Type Unthreaded Hole, Grit 24, Overall Diameter 4 in, Overall Thickness 0.125 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