1. 11 sizes of diamond hole saw: 5mm, 6mm, 8mm, 10mm, 12mm, 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, made of high strength 45# steel,The integrated steel structure makes these diamond drill bits more durable. 2. High quality diamond coated diamond hole saws improve drilling speed and create a clean, high precision and smooth cut without broken edges in seconds. 3. Adjustable hole saw drill guide jig attachment with suction base.The maximum opening length of the plates is 3-1/4, large enough to fit hole saws of all sizes. 4. Removable ball bearings, 2 modes (3 or 4 bearing attachment) are optional for you, just flip the plate.Hole saw or drill guide for drilling clear holes on tile, glass, marble, countertop, granite, etc. 5. Drill holes for Glass, Tile Bottles, Block Jars, Fiberglass Porcelain Tile, Ceramic, Mable Slate, Granite Clear Stone