High Quality Materials: This drill bit set is made of high quality emery material, electroplated, wear resistant, durable and long service life. High hardness and sharpness. Scientific Design: The diamond drill bit uses a scientific chip removal design to make the diamond drill bit group more stable, and the diamond tile shank has a circular design, which is widely used in electric hand drills and angle grinders. Single Detail: Diamond coating increases drilling speed. The round shank is compatible with most machines such as hand drills, angle grinders, bench drills, etc. Side grooves help remove dirt and drill holes smoothly and quickly. Depth markers are useful for specific projects. Wide Range Of Applications: The tile drill bit set is very suitable for drilling hard materials such as glass, ceramic tile, granite, marble, limestone, quartz, terrazzo, etc. Our diamond drill bits for tiles have several diamond segments that act as cutting teeth and Thus particularly precise and fast work allows working without breaking or falling. Packaging and Service: Contains 5 drill bits including 5mm, 6mm, 8mm, 10mm, 12mm to meet your different needs. If you have any questions, do not hesitate to contact me. I will get back to you within 24 hours. Note: The data is manual measurement, please allow 1-54cm error, due to light and screen differences, there there will be a certain color difference, the specific received in kind prevail.