This twist drill set features a straight shank design that is suitable for various electric drills and drill machines (not included). Its sharp and twisted flutes make drilling easier for wood, aluminum, plastic, and other materials. Perfect for DIY projects, household and general construction/engineering use, this set is titanium-plated and made of high-speed steel 4241, with the exception of the 3mm size which is high-carbon steel. It is ideal for drilling and reaming aluminum alloy, wood, jade, diamond, bodhi, and pvc board, but not recommended for stainless steel. The set includes sizes 1-3mm with respective twisted positions and a total length of 1mm, 1.5mm, 2mm, 2.5mm, and 3mm. Please note that the actual color of the item may vary slightly due to different monitors and lighting. Additionally, please allow for a 1-3mm measuring deviation due to manual measurement