High quality diamond drill bit set that won't rust and cuts quickly Made from high-strength carbon steel with a nickel-plated surface for durability and precision. The drill bit head features an 80-grit diamond coating for uniform cutting, increased drilling speed, and sharper performance compared to standard hole saws. 10-piece set with most commonly used sizes Includes 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, and 50mm diameters. Laser-marked sizing ensures easy identification and meets a wide range of application needs. Ideal for drilling glass, marble, tiles, porcelain, ceramic, slate, granite, fiberglass, and similar hard materials. Compatible with all standard electric drills and impact drills. Ergonomic design with center and side holes for efficient debris removal. The nickel-plated surface enhances corrosion resistance and extends tool life. Note: When drilling hard materials, always use water for cooling and lubrication to prevent overheating, reduce wear, and protect the material being drilled. Set includes: 10 diamond core drill bits. Material: Steel Applications: Suitable for stone, tile, ceramic, glass, and granite. Offers reliable performance and long service life, especially for clean and precise holes in glass and ceramic tiles. For best results, use with an electric drill (drill not included). Instructions: 1. Start drilling at a slight angle to create a guide mark, then proceed straight. 2. Always use water as a lubricant during operation to prevent overheating. 3. Designed for efficient cutting on concrete, tiles, and other hard surfaces with minimal heat buildup, reducing the risk of drill damage.