【Superb Craftsmanship】These diamond drill bits are made of industrial-grade carbon steel and have a nickel-plated coating to resist corrosion. Coated with high-quality diamond, the diamond hole saw creates a high precision, smooth cut with no broken edges. Reduced drill speeds, low drill pressure, and increased use of water lubrication will extend drill bit life considerably 【10 Different Sizes Diamond Hole Saw】6mm/0.23", 8mm/0.31", 10mm/0.39", 12mm/0.47", 20mm/0.78", 25mm/0.98", 30mm/1.18", 35mm/1.38", 40mm/1.57", 50mm/1.97". They are made of high-strength carbon steel makes these diamond drill bits durable. 【Adjustable Fxture】Adjustable hole saw 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. 【Ergonomic Design】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 hole saw. We can use our screwdriver to pull it out. To provide you with the perfect experience. 【Best Choice】This diamond-coated hole saw 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