The skirt body using the material of 45CrNiMnV(Chromium, Nickel, Manganese, Vanadium)alloy steel, taking the heat-inlay fasten buttons technology, when the drill bit drilling, the drill bit temperature can reach to 600-700 degrees, but our button bit skirt body is still have a good force to hold the buttons, and it's very rare to appear the buttons take off the body and body failure. We use the Boart longYear and the Chinese famous brand's cemented carbide, it's wearing resistance and bending resistance both are very good.