【Professional Diamond Hole Saw】Made of selected high-strength carbon steel and diamond-coated drill bit, excellent cutting ability, rustproof and durable, high torque and long life. 【High-quality Drilling】The diamond coating can increase drilling speed and make the bit sharper. The cutting edge design makes resistance smaller and more efficient, helping to drill a smooth round hole with precision. Side hole for round chips to keep the bit always clean. 【Ideal for】Diamond brazing specially designed for porcelain, glass, marble, ceramic, rock, and granite, etc. 【Tips for use】First, cut a 45° bevel, open the positioning crescent groove, then slowly raise the hole opener and drill at a uniform speed. Also, keep the bit moist while drilling to avoid overheating. 【Buy with confidence】If you have any questions, please feel free to contact us. We will do our best to resolve them. (Please clamp the arbor in the correct position and take necessary protective measures when working with wood.)