Five Pieces | 7" Double Row Diamond Cup Grinding wheels 7" Diameter | Double rim provides longer life and more aggressive hard material removal Extended performance diamond matrix provides 350x's the life of conventional abrasives Cup wheels feature venting holes for fast, rough, dry or water cooling grinding Large grinding segments with heat treated steel bodies which provides increases durability 5/8-11 Threaded Arbor | For use with small/large angle grinders