Alloy Blades: Tungsten Carbide Blades Have High Cutting Efficiency and Less Dust. Smooth Running: Closed Bearollers Are Easy to Align for Precise Cutting, Better Performance and Longer Service Life. Teflon Coating: Drill Bits Are Used Effectively for Many Times Without Affecting the Quality of the Drill Bits Suitable for Composite Materials, Veneer Plywood, Hardwood, Softwood, Etc. Alloy Steel Shank:Y Steel Shank with High Strength and Goodhinability, Manufacturer: CHAOUYYZ