NortonĀ® GeminiĀ® 66252843597 Grinding Wheel, Type 27 Depressed Center, Outside Diameter: 5 Inch, Thickness: 1/4 Inch, Arbor Hole / Thread Size: 5/8-11 Thread, Abrasive Type: Aluminum Oxide, Max Speed: 12225 Rpm, Mounting: Threaded, Product / Materials Abraded: Metal/Stainless Steel