DeWALT® High Performance™ Guaranteed Tough® Depressed Center Grinding Wheel, Flat, 4-1/2 in Wheel dia, 1/4 in Wheel, 7/8 in Center Hole, Arbor Connector, 24 Grit, Coarse Grade, Aluminum Oxide Abrasive, Wheel Type Number: Type 27, 13300 RPM Maximum, Resin Bond, Applicable Materials: Ferrous Metal and Stainless Steel, Wheel Hardness: N, Reinforced: Yes, Specifications Met: ANSI Specified. DeWALT® High Performance™ Guaranteed Tough® DW4541 Flat Depressed Center Grinding Wheel, 4-1/2 in dia x 1/4 in Thick