Depressed Center Wheels, Abrasive Wheel Type Type 27, Abrasive Wheel Diameter 7 in, Thickness 0.25 in, Arbor Hole Size 5/8 In. -11, Abrasive Material Aluminum Oxide, Abrasive Grit 24, Max. RPM 8, 500 RPM, Series A24R, Grade Very Coarse, Application Ferrous Metal