High Quality: The drill bit set is made of high quality tungsten steel, processing hardness up to HRA 85, perfect for iron, steel, carbon steel, alloy steel, stainless steel, copper, aluminum etc. Drill Applicable: The drill bit set fits most rotary tools such as Dremel, Proxxon, Mister Tool, Einhell and similar machines, diameter shank diameter: 3mm, cutting edge diameter: 6mm, total length: 43.5~50mm Multi-function: The carving bit set can be used for engraving, chamfering, slotting, boring, hollowing, etc. The processing efficiency is ten times higher than that of the manual sanding tool and almost ten times higher than the small grinding wheel with the handle Wide application: the rotary grinding wheels can be used for the engraving and milling of soft wood, plastic and other soft materials, after carving, the surface will be smooth Portable: Rotary grinding wheels come in a portable box, no need to keep order