Material: Tungsten steel Solid Carbide Total length:100m(3.9inch ) Shank length:80mm Shank diameter:6mm(1/4 inch) Grinding head diameter:10mm Package include: 1pcs 3.9inch Extened Long Tungsten Carbide Burr Note: Supporting the drive tool fixture concentricity is better, is strictly prohibited and different use of the fixture supporting the use of the handle must be clamped, folder is running. The operation is strictly prohibited shaking phenomenon, cutting direction should move from right to left, do not Too much force to prevent bounce, impact, handle length of more than 80MM should be slow down operation, to prevent chip flying, please use protective glasses.