Depressed Center Grinding 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 0.25 in Primary Material Applicationn Stainless Steel Compatible Tool Type Angle Grinder Series A30S Wheel Type Type 27 Maximum Operating Speed 13 300 RPM Grade Extra Coarse