Depressed Center -Off Wheel, Abrasive Material Aluminum Oxide, Connector Size 5/8 In.-11, Connector Type Threaded Hole, Grit 30, Overall Diameter 4 1/2 in, Overall Thickness 0.045 in, Primary Material Applicationn Steel, Compatible Tool Type Angle Grinder, Series Carbo Gold , Wheel Type Type 27, Maximum Operating Speed 13,580 RPM, Grade T