High quality: The drill bit set is made of high-quality tungsten steel, with a machining hardness of up to HRA 85, perfect for iron, steel, carbon steel, alloy steel, stainless steel, copper, aluminum, etc. Applicable drill: The drill bit set fits most rotary tools such as Dremel, Proxxon, Mister Tool, Einhell and similar machines, shank diameter: 3 mm, cutting edge diameter: 6 mm, total length: 43.5 ~ 50 mm Multifunction: The carving drill bit set can be used for engraving, chamfering, grooving, reaming, hollowing, etc. The processing efficiency is ten times higher than that of the manual sanding tool and almost ten times higher than the small handle grinding wheel. Wide application: Rotary grinding wheels can be used for engraving and milling softwood, 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.