IVY Classic 40258 Swift Cut 9-Inch x 1/4-Inch x 5/8-Inch - 11 Threaded Arbor, Metal Depressed Center Wheel with Hub for Grinders, 1-Piece Designed for consistent, all purpose grinding of steel, angle iron, sheet metal and other ferrous metal products, Swift Cut (Registered Trademark) Resin bonded Aluminum-Oxide grain for faster grinding, Type 27 blade - for grinding only Blade double reinforced with fiberglass mesh for durability and safety Arbor reinforced with metal for extra strength Diameter: 9-inch, Width: 1/4-inch, Arbor: 5/8-inch - 11 thread, Max RPM: 6,600