Our diamond hole saw with positioning pilot bit is made of high-quality diamond, solid hardened steel body, and the surface is designed with nickel-plated coating, ensuring its high hardness, rust proof, anti-corrosion, sturdy and durable.Each tile hole saw is designed with a detachable Positioning pilot drill bit, and the cutter head of the pilot drill bit is also designed with diamond coating, which makes it sharper and more durable, and efficiently!