Depressed Center Grinding Wheel, Abrasive Material Aluminum Oxide, Connector Size 5/8 In.-11, Connector Type Threaded Hole, Grit 24, Overall Diameter 4 1/2 in, Overall Thickness 0.25 in, Primary Material Application Steel, Compatible Tool Type Angle Grinder, Series Metal AO, Wheel Type Type 27, Maximum Operating Speed 13,300 RPM, Grade Extra Coarse