Outstanding Design: Unique design with perfect perforation effect. The saw will be automatically unloaded from the top of the holes on both sides, without drilling blocked. Easy to replace and install: According to the hardness of the wood, you can choose different center drills, disassemble the screw and you can replace the drill easily. At the same time, quickly change the bits that load and release with one hand. Multi-function: drill for precise positioning, without movement. Applicable for door hinge installation. Various Sizes: Includes 2 different sizes of 1/4" hinge screws, 5mm for carpenters, cabinets, furniture makers and other construction trades. wood. High quality material: made of high speed steel, with high hardness, rust resistant, strong, durable and excellent for using.