MULTIPLE SIZE - This PCB drill bit set contains 10 different size: 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, each size has 5pcs; Varies sizes to meet different needs. HIGH QUALITY - Made of high quality tungsten steel, highly wear resistance, high hardness, bending strength, anti-impairment, with good milling and cutting performance, ensuring high efficiency. HIGH PRECISION - PCB Tip spiral flute reduces cutting force and improves hole accuracy.With , milling groove and clean , these sets of tool work quickly and cleanly, no glitches or scrap left. APPLICATION - Great for 3D Printer Nozzle Cleaning, Amber beeswax, circuit boards, bakelite, CNC engraving, jewelery, metal plastic and other precision drilling. ATTENTION - Shank diameter: . 1/8 (3.175mm) ; Total length: 1.5 inch(38.1mm); This drill is used on precision machines such as desktop engraving machines and high-speed rotary tables. Hand-held electric drills require high operating technology.