DeWALT® High Performance™ Guaranteed Tough® Surface Grinding Cup Wheel, 4 in Wheel dia, 2 in Wheel, 16 Grit, Coarse Grade, Aluminum Oxide Abrasive, Wheel Type Number: Type 11, 9000 rpm Maximum, Wheel Hardness: R, Resin Bond, Applicable Materials: Ferrous Metal, 5/8-11 Center Hole Thread, Cup Wheel, Specifications Met: ANSI Specified. DeWALT® DW4960 High Performance™ Guaranteed Tough® Surface Grinding Cup Wheel, 4 in dia x 2 in Thick, 16 Grit