Depressed Center Grinding Wheel, Abrasive Material Aluminum Oxide, Connector Size 3/8 in, Connector Type Unthreaded Hole, Grit 24, Overall Diameter 4 in, Overall Thickness 0.25 in, Primary Material Applicationn Steel, Compatible Tool Type Angle Grinder, Series A24N, Wheel Type Type 27, Maximum Operating Speed 13,500 RPM, Grade Extra Coarse