DeWALT® High Performance™ Guaranteed Tough® Depressed Center Grinding Wheel, Flat, 7 in Wheel dia, 1/8 in Wheel, Threaded Arbor Connector, 24 Grit, Coarse Grade, Aluminum Oxide Abrasive, Wheel Type Number: Type 27, 8700 RPM Maximum, Resin Bond, Applicable Materials: Pipeline, Stainless Steel, Ferrous and Non-Ferrous Metal, 5/8-11 Center Hole Thread, Wheel Hardness: R, Reinforced: Yes, Specifications Met: ANSI Specified. DeWALT® DW8437 High Performance™ Guaranteed Tough® Flat Depressed Center Grinding Wheel, 7 in dia x 1/8 in Thick, 24 Grit