Camel Grinding Wheels® 49000 Cup Stone, Type 11, Diameter: 4 Inch, Length: 2 Inch, Grade: Q, Grit: 16, Abrasive Type: Aluminum Oxide, Max Speed: 9070 Rpm, Bore / Shank Diameter: 5/8-11, Shape/Form: Cup, Mounting: Threaded, Product / Materials Abraded: Tough Steel And Ferrous Metals