Sait® 20015 Grinding Wheel, Type 27, Outside Diameter: 4 Inch, Thickness: 1/4 Inch, Arbor Hole / Thread Size: 5/8 Inch A.H., Grade: N, Grit: 24 (Coarse), Abrasive Type: Aluminum Oxide, Max Speed: 13500 Rpm, Mounting: Arbor, Product / Materials Abraded: Metal