Perfect size: For precise drilling of different sizes from 5-35mm in diameter, one drill can handle holes of different sizes. High quality material: the titanium alloy liner is made of high quality HSS , which can ensure extremely high durability and reduce friction and heat. Titanium alloy drill bits are especially suitable for processing thin copper and aluminum workpieces / iron plates / wooden panels / plastic plates and other thin plate materials. Easy to drill: Marking hole position and double flute design make drilling faster and smoother, as well as precise drilling. Laser size: The dimensions are laser etched into the metal so they won't wear out even after repeated use. Applicable materials: plastic, wood, copper, iron, fiberglass, PVC, fin metal and aluminum3mm Note: The data is all manual measurement, please allow 1-3cm error; due to the difference in light and display, there would be some color difference, please refer to the actual item received.