5/16″ x 12″, High Speed Split Point Drill Bit, Helix Is 31&degree. Which Minimizes The Over Aggressiveness Of A True Parabolic Flute, 135&degree. Split Point For Quick Start & No Walk Applications, Parabolic Flute Design Improves Chip Ejection In Metal & Wood Drilling Applications, Back Oxide Coating For Greater Resistance To Wear, Industrial Grade Steel, For Drilling In Metal, Wood & Plastic.