Features Versatile Compatibility: Perfect for drilling into a wide range of materials including stainless steel, copper, and plastics, making it an essential tool for various projects Enhanced Performance Design: Features double back angles that ensure self-centering, significantly reducing drilling resistance and heat buildup for efficient operation Reduced Resistance: Short chisel edge design minimizes drilling resistance, allowing for smoother operation and longer tool life during use Comprehensive Size Range: Includes 25 different sizes from 1mm to 1m, ensuring you have the right drill bit for any application or task at hand Durable High-Speed Steel: Constructed from premium high-speed steel, these drill bits offer superior hardness and longevity, ensuring reliable performance over time Features: 1、Suitable for drilling of stainl steel, die steel, alloy steel, non-alloy copper, gray cast iron, ductile cast iron, malleable cast steel, spring steel, iron, copper, and other metals and plastics (note: hardened steel depending on the situation). 2、Straight shank twisted drill has double back angles, self-centering does not allow pre-set holes, reducing drilling resistance, reducing heat, and more drill bits. 3、Short chisel edge reduces drilling resistance. 4、25 sizes (1-1m), (1mm / 1.5mm / 2mm / 2.5mm / m / 3.5mm / 4mm / 4.5mm / 5mm / 5.5mm / 6mm / 6.5mm / 7mm / 7.5mm / 8mm / 8.5mm / 9mm / 9.5mm / 10mm / 10.5mm / 11mm / 11.5mm / 12mm / 12.5 mm / 1m). 5、Made of high-quality high-speed steel, high hardn and long service life. Specification: Item Type: Drill Bits Material: High-speed steel Size: Includes a size range of 1mm to 1m (1mm / 1.5mm / 2mm / 2.5mm / m / 3.5mm / 4mm / 4.5mm / 5mm / 5.5mm / 6mm / 6.5mm / 7mm / 7.5mm / 8mm / 8.5mm / 9mm / 9.5mm / 10mm / 10.5mm / 11mm / 11.5mm / 12mm / 12.5 mm / 1m) Package List: 25 x Twisted Drill Bits 1 x Iron Box Package List 25 x Twisted Drill Bits 1 x Iron Box