Heat treated hardened steel. High strength, good toughness and high occlusal degree. Very easy to be installed and dismantled, will not fall off during usage. Fits almost all the powered corded and cordless drills with 1/4 Inch or 6mm shank. 6mm Hex Shank (Fits All Drills And Power Drivers). The bell-shape and magnetic hex insert allow to hold the bit securely in place for quicker installations. Designed and engined for long life and good durability for operating. Used in manufacturing assembly systems and others. Strong magnetism for convenient operation.