Kutzall Original Sphere Burr, 1/8" Shaft (3.1mm) - Fine, Tungsten Carbide Coating: 3/8" (9.5mm) Head Diameter x 3/8" (9.5mm) Head Length - S-38-EG Rapid Material Removal - Saving you time and effort. Tungsten Carbide Teeth - Giving you outstanding wear-life, for a much longer lasting burr. Comfortable, Effortless Operation - Allowing you to easily and quickly remove a variety of materials. Leaves a relatively smooth finish. Should only be used on non-metals or non-metallic materials.