SIZE - 9mm(0.35-inch) Drilling Diameter, 6.5mm(0.26-inch) Shank Diameter. The hole saw achieves high precision and smooth cuts without edge breakage, with good toughness and high strength. DIAMOND COATED - Diamond coating enhances the drilling speed, which makes the bit more sharp.Electroplated diamond is uniform and more wear-resistant. NICKEL PLATED SURFACE - Nickel plating surface can extend the service life and enhance the surface corrosion resistance. Diamond coating maximizes performance and retains a sharper cutting edge than traditional carbide or bimetal hole saws. SPECIAL DESIGN - The diamond hole saw with clearance hole facilitates the entry of cooling water and the escape of chips from the drilled hole. Makes the drilling process easier. Not suitable for drilling tempered glass, plastic and wood. APPLICATIONS - Perfect for drilling glass, ceramics, porcelain, ceramic tile, porcelain tile, limestone, slate, marble, light stone and fiberglass. (Need to be used at a low speed; Always use lubrication (water) when processing, otherwise the hole saw will burn.)