Features: These carbide rotary burr set, with 1/4 inch shank and the diameter of the grinding head is 6-12mm, 0.25-0.47 inch, is made from Tungsten Carbide. These rotary burr set is ideal for DIY woodworking, carving, engraving, grinding and polishing, which is a good assistant for you to work. These rotary tool bits are made with premium carbide tungsten steel with high strength and durability which can allow you to use for a long time. Using these rotary burr set with a rotary tool, is 10 times higher than the manual file tool. In most jobs, it can replace petiole wheel without dust pollution. Include 8 types grinding heads with different sizes, You can choose the suitable one as your working needs.