Wide range of applications: Ceramic tile drill bits are suitable for all electric drills. Widely used in glass, ceramic tile, porcelain, floor tile, marble, granite, and other similar materials. Not suitable for tempered glass, concrete, or masonry deeper than 1/2 inch. High quality: The tip of the diamond drill bit is made of nickel-plated high-speed steel (HSS) with an 80-100 grit diamond coating. Fast cutting: The diamond hole saw blade is coated for sharp, high-precision, smooth cutting with no bending, allowing for clean and accurate holes. The center guide hole and side holes help remove debris. Usage: This hole saw glass drill bit set is compatible with all electric drills and impact drills. Maintain a speed of 800-1000 RPM. Continuously apply water to keep the drill bit cool. Dry drilling is strictly prohibited. Package: 15-piece hole saw set in sizes 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, 26mm, 28mm, 30mm, 40mm, and 50mm. Quantity and sizes meet everyday needs. Specifications: Material: Carbon steel. 15-piece diamond hole saw bit set, 6mm–50mm. Features: Diamond core bit designed to cut clean, full circles in glass, tile, marble, granite, ceramic, and similar materials. Color: Silver. Shank diameter: 6mm drill bits have a 6mm shank; 8mm to 25mm drill bits have an 8mm shank; all other sizes have a 10mm shank. Notes: If a burning smell occurs, stop immediately—speed or pressure may be too high. Do not touch the drill bit during or immediately after use. Always use water for cooling; failure to do so may damage the bit. Compatible with standard electric drills. Start with light pressure to create a pilot mark, then maintain a straight drilling angle. Reducing speed, minimizing pressure, and increasing water use can extend bit life. Use coolant during operation. Apply minimal pressure. Smaller diameter bits can use higher speeds; harder materials require slower speeds. Package includes: 15 diamond brazing drill bits