The Alpen 4.0mm HSS Dowel Drill with 1/4" Hex features cobalt alloyed high-speed steel, offering excellent heat resistance for drilling steels with tensile strength up to 800 N/mm². Ideal for high alloyed steels, bearing steels, and stainless steel. Brand: Alpen Diameter: 4.0mm Shank: 1/4" Hex Material: Cobalt alloyed high-speed steel (HSS) Heat Resistance: High, for drilling steel with tensile strength over 800 N/mm² Application: Suitable for high alloyed steels, bearing steels, hot/cold rolled steels, and stainless steel Precision for accurate dowel holes