NortonĀ® Metal 66252843614 Grinding Wheel, Type 27 Depressed Center, Outside Diameter: 5 Inch, Thickness: 1/4 Inch, Arbor Hole / Thread Size: 7/8 Inch A.H., Abrasive Type: Aluminum Oxide, Max Speed: 12225 Rpm, Mounting: Arbor, Product / Materials Abraded: Metal/Stainless Steel