Suitable for cuttingSS, Steel, Alluminium, copper Acrylic, fiber MS etc. 100 percent high quality and brand new. The gears is made from yg8 tungsten carbide steel and the rigidity varies from the hole saw has a twist drill bit inside, which is undetachable. Sharp gears and anti-cutting with lower consumption make the product a long service life. Carbide teeth for fast cutting of clean, round holes. Suitable for hand held electric drill, stand motor-driven drilling machine and mobile ribbon type magnetism drilling machine. Cuts quick, precise holes in stainless steel, mild steel, iron, copper and brass. Can drill about 20mm depth please note that if you cut the hard material such as steel, ceramic tile