Total length: 56-65mm, stem: 6mm, drill diameter: 8mm, suitable for dremel and most small rotary tools Made of high strength treated tungsten carbide, high abrasion resistance and good toughness. Mechanical parts chamfering, rounding and grooving.Double slit is cross lines, not easy to block lines, more suitable for relatively low density material object The rotary cutter set has high production efficiency , with 10 times higher than the manual file tool, and nearly 10 times higher than the small grinding wheel with the handle. In most cases, it can replace a small grinding wheel without dust pollution Suitable for metal polishing, wood carving, jewelry, hobbies, crafts, craft style , home repair, etc Mechanical parts chamfering, rounding and grooving. Double slot is cross lines, not easy to block lines, more suitable for relatively low density material object. The double cut style has rows of cutting teeth cut in two directions that intersect for fast material removal and a rougher finish. Suitable for metal working, tool making, modelling, wood carving, jewelry making, fabrication, welding, chamfering, casting, deburring, grinding, etc. Specifications: Shank Diameter: 6mm(1/4 inch) Drill Diameter: 8mm Material: tungsten carbide Caution When using drill bits, material temperature will be very high, please add water or coolant to avoid being burned. Not available for bench drilling machine.