"PREMIUM CARBIDE BUR SET: This set includes 8 of the most popular shapes in a fitted case. With a 1/4 inch shank, suitable for processing various metals and most rotary grinders. Excellent choice for precise metal removal when shaping, leveling or porting cast iron, steel and other ferrous metals. ADVANCES TUNSTEN MATERIAL: 100% burr free Raw virgin tungsten carbide whose service life is very long, 10 times the durability of other HSS milling cutters and 200 times the durability of the small wheel. The hardness can reach HRC70, sharp and sturdy. PRECISE DOUBLE CUT: Double cut style, the right and left helical flutes combine to produce a chisel-like cutting tooth, this precision, when combined with precision grinders, results in a smooth operation, rapid metal removal and fine finishes. WIDELY APPLICATION: Widely used for metal working, tool making, model engineering, wood carving , jewelry making, welding, chamfering, casting, deburring, grinding, breech porting and carving. Include body shops, fabrication shops, brake shops, industrial shops, die makers. SIZE ORMATION Shank Dia: 6mm (1/4 inch ) Fits for most rotary tools with 1/4"" chuck, large size head can do better carving and grinding jobs. Made of heat-treated tungsten carbide material, sharp and wear-resistant, can bring high efficiency grinding and carving experiences. VARIOUS SHAPE This kit includes 8 different shapes of head, 1pc for each shape with double cut, can meet your different requirements. ON WOOD Double-cut file, suitable for wood, aluminum and other soft metal material. Mainly be used with electric or air tools. ON PURE COPPER Can be used for metal or nonmetal carving, mold cavity processing, impeller passage grinding and so on. ON ALUMINUM Suggest rotating speed is between 6000-50000rpm. The cutting file should be placed in a correct place and suggest to wear safety goggles while operating."