General description Professional quality Cobalt Metal Drill Bit Set Hole Saw. This set includes five drill bits with diameters of 16 mm, 18.5 mm, 20 mm, 25 mm, and 30 mm, made from high-speed steel with 5% cobalt, ensuring high resistance and durability. Ideal for drilling through steel, aluminum, metal, wood, and plastic materials. Technical specifications Material: HSS Cobalt (M35) Hardness: HRC 64–66 Shank diameter: 9.5 mm Working length: 1.5 cm Diameter sizes: 16 mm, 18.5 mm, 20 mm, 25 mm, 30 mm Usage Suitable for drilling in steel, aluminum, plastic, and wood. Other information