Features: Great addition to your hobby craft tool kit Diamond coating is on both sides of the disc Ideal For Cutting: Gem stones, metal, glass, carbide and other hard material Grain fineness number: Approx. 150 Disc Diameter: Approx. 60 mm Disc Thickness: Approx. 0.5mm Center Hole Diameter: Approx. 3 mm Shank Diameter: Approx. 3.1 mm Material: Carbon steel 18mm cutting discs with diamond coating on both sides. Come with 3.1mm diameter mandrel, these cutting discs will fit most rotary tools. These cutting discs are perfect for all sorts of jobs like model making and the like. Package Includes 1 x Cutting Disc 1 x Mandrel