【10 SIZES DIAMOND TREE 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, making these diamond drill bits durable. 【ADJUSTABLE HOLE SAW DRILL GUIDE】 Adjustable hole saw drill guide attachment with suction cup - the maximum opening length of the board is 3-1/4", which is large enough to fit any hole saw size. Movable ball bearings, two modes (3 or 4 bearing attachment) are your choice, just turn the board over. 【HIGH QUALITY】 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 smooth, high-precision cut without broken edges. Reduced drilling speeds, low drilling pressure, and increased use of water lubrication will significantly extend the life of the drill bit. 【WIDELY USED】 This diamond core bit can be used to remove rings on glass,