IVY Classic 41308 Swift Cut 9-Inch x 1/4-Inch x 5/8-Inch - 11 Threaded Arbor, Masonry Depressed Center Wheel With Hub for Grinders, 1-Piece Designed for consistent, all purpose grinding of brick, concrete block, slate, tile and other masonry products, Swift Cut (Registered Trademark) Resin bonded Silicon-Carbide 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