Feature: 1. Suitable for drilling of stainless 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 durable drill bits. 3. Short chisel edge reduces drilling resistance. 4. 25 sizes (1-13mm), (1mm / 1.5mm / 2mm / 2.5mm / 3mm / 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 / 13mm). 5. Made of high-quality high-speed steel, high hardness and long service life. Specification: Item Type: Drill Bits Material: High-speed steel Size: Includes a size range of 1mm to 13mm (1mm / 1.5mm / 2mm / 2.5mm / 3mm / 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 / 13mm). Package List: 25 x Twisted Drill Bits1 x Iron Box