Description: Superb craftsmanship: These diamond drill bits are made of industrial grade carbon steel and have a nickel-plated coating to resist corrosion. The thickened diamond coating on the top provides excellent cutting strength for high-precision, smooth cuts without hemming for maximum drilling results. The large clearance holes along the drill bit help the entry of cooling water and the escape of chips and other particles from the borehole, ensuring smooth punching and making the drilling process easier. Small holes-When debris gets stuck in the . We can use our screwdriver to pull it out. To provide you with the perfect experience. Adjustable fixture: Adjustable drilling guide fixture with suction cup-the maximum opening length of the board is 3-1 / 4 ", which is large enough to fit in all size hole saws. Movable ball bearings, two modes (fixing 3 or 4 bearings) are your choice, just flip the board. Various sizes: This diamond kit come with different drill bits to meet various needs. This diamond-coated bit can be used to remove rings on glass, marble, tile, ceramic, PVC or other materials. When the diamond bit is working, please continue to add water to reduce the drilling speed, reduce the drilling pressure, and increase the water lubricity, which will greatly extend the life of the bit. Specification: Material: Steel and Rubber Size Chart: 21.5x14cm/8.46x5.51inch Package Includes: 1 Set Diamond Drill Bit Set Note: 1. Please allow slightly error due to manual measurement. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. 3. Wish you a wonderful on-line shopping!