1. Premium Material and Design: Made of tungsten steel, extremely hard, tough, durable, heatproof and anti-corrosion. Special double cut design for improved work efficiency. Head groove lines are crossed for quick chip removal on materials like wood, metal, marble, jade and more. 2. Various Sizes and Shapes: Tungsten steel burr set comes in different shapes including end cut cylindrical, ball nosed cylindrical, ball, oval, ball nosed tree, tree, flame, ball nosed cone, cone, inverted cone. Shank diameter is 1/8''(3mm), cutting diameter 1/4''(6mm), total length 40 - 50mm. 3. High Work Efficiency: Processing efficiency is tens times higher than manual file tools and nearly ten times higher than small grinding wheels with handle. Can replace small grinding wheel. Recommended speed is 6000 - 60000RPM. Pass tool rapidly over workpiece for fine finishes. 4. Wide Application: Fits most rotary tools. Ideal for DIY woodworking, carving, engraving, polishing, cutting, jewelry making, casting, grinding and more. Excellent for fine detail work. 5. Tips: Generally used with handheld electric or pneumatic tool drive. Speed of tools is usually 6000 - 50000 revolutions per minute. Packed in plastic storage case for safety and protection.