Features: Made of carbon steel material, high hardness, high toughness, wear resistance and can provide long service time. Polishing surface processing, rustproof, anti-corrosion and beautiful. The shank uses 60# carbon steel material, high strength and not easy to deformation, with fine durability. The blades and shanks are adopts seamless welding, with nice welding effect. Wide applications, suitable for coring operation, trepan boring, dowel connection of wood and etc.. It can be applied on the composite board, compressed panel, and other wood boards. Do not suitable for glass, metal, plasterboard, concrete. 5 types available, you can choose 15mm, 20mm, 25mm, 30mm, 40mm according to your demands.