IRWIN 1890736 Flexible Extension for Installer Drill Bits, 1/4-Inch Shank and 1/4-Inch Connection, 36-Inch Length Chuck is compatible with round, hex and quick-change shank drill bits High carbon steel construction for durability and life Bits lock in place when set screw is tightened with hex key 3-flatted shank prevents slipping in drill chuck and includes hole for wire pulling