The drill bits are made of fine-quality high speed steel with nitrogen treating surface, high hardness and wear resistance, with long durability and strong drilling power. 1/4inch/6.35mm straight shank design allows this drill bits to be inserted directly into a drill jig or drill press for easy installation. 15pcs/set, include 5 sizes of drill bits(3/4/5mm), and 5pcs each sizes,  to meet your different needs perfectly. Perfect for DIY wood working, home use and general building, engineering using. Features: Made of fine-quality high speed steel with nitrogen treating surface, high hardness and wear resistance, with long durability and strong drilling power. 1/4inch/6.35mm straight shank design allows this drill bits to be inserted directly into a drill jig or drill press for easy installation. 15pcs/set, include 5 sizes of drill bits(3/4/5mm), and 5pcs each sizes,  to meet your different needs perfectly. Spiral grooves design makes smoother chip removal and reduces friction and heat accumulation for higher efficiency, with high efficient drilling performance. Wide applications, it can be used to drill wood, plastics, metal and other materials. Perfect for DIY wood working, home use and general building, engineering using. Specifications: Name: Drill Bits Set Material: high speed steel Shank diameter: 1/4inch 6.35mm Item size: 3.0mm: 82 * 3.0 * 3.0mm / 3.23 * 0.12 * 0.12in 4.0mm: 94 * 4.0 * 4.0mm / 3.70 * 0.16 * 0.16in 5.0mm: 104 * 5.0 * 5.0mm / 4.09 * 0.20 * 0.20in Package size: 130 * 80 * 50mm / 5.12 * 3.15 * 1.97in Package weight: 180g / 6.35ounce Packing List: 15 * Drill Bits