DoubleLok Technology ensures both ends of bit lock securely in impact drivers and quick change chucks, enabling use of a single bit to remove stripped, damaged or rusted screws and small bolts in three easy steps: drill, flip bit, and extract. Manufactured with M2 high speed steel and extra-hardened for maximum durability and long life with impact drivers. Tip of drill end is designed to start fast with minimal walking, and tip of extractor end is serrated for increased torque to remove even the toughest screws and bolts. Set includes 1 each: DE-1, DE-2, DE-3 screw extractors.