Kutzall Original Ball Nose Burr, 1/4" Shaft (6.3mm) - Fine, Tungsten Carbide Coating: 1/4" (6.3mm) Head Diameter x 1-1/2" (38.1mm) Head Length - BN-14G 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.