【Material】: Heat treated tungsten carbide steel. High hardness and heat resistance, the high temperature generated during drilling will not be deformed, also wear-resistant, can be used for a very long time. High concentricity, so the processing accuracy is high and the noise is low. 【3 Large Pieces】: Package includes 65/70/80mm. The circular rim guide drills all arcs of circles in all directions, ensures a true, accurate, clean and flat-bottomed hole with fast waste removal, for efficient work. 【X-wing Design for Accuracy】: The X-wing head provides visibility and stability during operation. The center point of each drill bit ensures accurate drilling and eliminates kicking and wobbling during operation. The center spur construction creates perfectly round and accurate holes. 【Decorative Hole Drilling】: Suitable for drill, pistol drill, bench drill, vertical drill, hand electric drill, motorized drill and magnetic drill with movable adhesive tape to mount the tip of the door ball,