IRWIN 1890948 Flexible Installer Drill Bit with High-Speed Steel Tip, 3/8-Inch Shank, 36-Inch Length Unique combination of 135 Degree self-centering split point stepped to 118 Degree hole enlarging body for fast, easy starts and smooth drilling Hole in flute for easy wire pulling through walls, ceilings and floors 3-flatted shank prevents slipping in drill chuck and includes hole for wire pulling Tapered flute for faster chip ejection, less binding and smoother drilling Does not apply to 1/4" diameter SKUs Premium high speed steel construction for extended drilling life in metal, wood and plastic