Suitable for Initial Hole Machining of Pre-drill Holes to Ensure Drilling Accuracy Unique One-piece Design,can be Chamfering Work on NC and CNC machine tools(not recommended to use the Hand Electric Drill), General Use for Steels, Stainless Steel, Cast Iron, Plastic, Brass. Micro Carbide Material Improve the Tool Life More than Twice HSS Drills Large Spiral Flute to Make Sure the Chip Remove Smoothly, Reduce Burs