Depressed Center Wheels, Abrasive Material Ceramic, Connector Size 5/8 In.-11, Connector Type Threaded Hole, Grit 36, Overall Diameter 4 1/2 in, Overall Thickness 0.045 in, Primary Material Applicationn Aluminum, Stainless Steel, Series CUBITRON II, Wheel Type Type 27, Maximum Operating Speed 13,300 RPM, Grade Extra Coarse