Description:-The grinding wheel head has high hardness, high sharpness, wear and tear.-Its hardness is similar to that of white corundum, but its strength is higher than that of white corundum.-The grit of the grinding head is uniform, the abrasive grains are not easy to fall off, so the service life is long.-Widely used, mainly used for grinding and polishing various metal molds and chainsaw, for grinding inner wall hole, mold modification.-Used in electric grinder, suspension grinder, handheld electric drill and other machines.-4.0mm grinding head is suitable for small 8 chains and chain chains.-4.8mm grinding head for 325, Big 3/8 chain.-5.5mm for 404 chains. Specification:-Material: Red Corundum & Metal-Head Diameter: 4.0mm, 4.8mm, 5.5mm-Shank Diameter: 3mm (Approx. 1/8")-Total Length: 48mm-Head Length: 24mm-Color: As Picture Shown-Quantity: 2 PcsPackage Included:2 Pcs. Alumina grinding head (size depends on your choice!)Note:-Please allow 1-2mm errors due to manual measurement. The dot and color displayed in photos may be showing slightly different when showing on a computer monitor since monitors are not calibrated same.