NortonĀ® GeminiĀ® 66243510512 Cup Stone, Type 11, Diameter: 4 Inch Face, 3 Inch Back, Length: 2 Inch, Wall Thickness: 3/4 Inch, Grade: Q, Grit: 16, Abrasive Type: Aluminum Oxide, Bond Type: Resin, Max Speed: 9070 Rpm, Bore / Shank Diameter: 5/8-11, Shape/Form: Cup, Mounting: Threaded, Product / Materials Abraded: Metals