Safe: PCB drill bits are made of quality tungsten carbide, not easy to wear and bend; The anti-vibration design of the blade makes it stable and reliable during the engraving process Improve precision: mini drill bits set adopts pointed cutting edges; The spiral cutting edge can reduce the cutting force, prevent the drill from breaking, and improve the machining accuracy, no burrs or debris Size information: PCB drill bit set contains various sizes of drill diameter, 0.3 mm\/ 0.012 inch, 0.4 mm\/ 0.016 inch, 0.5 mm\/ 0.020 inch, 0.6 mm\/ 0.024 inch, 0.7 mm\/ 0.028 inch, 0.8 mm\/ 0.032 inch, 0.9 mm\/ 0.035 inch, 1 mm\/ 0.039 inch, 1.1 mm\/ 0.043 inch, 1.2 mm\/ 0.047 inch, each size has 3 pieces, totally 30 pieces in 3 boxes Wide usage: 0.01-0.05 inch drill bits set is suitable for processing precision drilling of amber beeswax, circuit boards, CNC engraved jewelry, hardware, plastics and so on colour: silver Material: tungsten carbide Package Contents: 30 x Mini drill bits Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +\/- 1-3cm.