【Efficient Four-Blade Design】: Cuts cleaner and faster, improving drilling efficiency. Drilling is precise and smooth, saving time and energy. Four chip flutes for faster drilling and more efficient chip evacuation. Screw extractor. [Professional Drill Bits]: These carbon steel drill bits have a threaded self-tapping drill tip for fast and accurate positioning. Universal hexagonal square handle, not easy to slip, suitable for electric drills, bench drills, cordless drills and other metal drills. [Durable Alloy Construction]: These black screw drill bits are made of 45 high carbon steel, durable and can be used on wooden furniture, wooden boards, plastics and more. They are frequently used in woodworking projects and provide reliable performance. Trust their longevity and long-lasting effects. Concrete Drill Bit. [9 Sizes Versatile Set]: The wood drill bit set includes 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, and 32mm. Its versatile size offers convenience and flexibility,