10 Sizes(Diameter): 6mm/0.23", 8mm/0.31", 10mm/0.39", 12mm/0.47", 14mm/0.55", 16mm/0.62", 18mm/0.7", 22mm/0.86", 30mm/1.2". Satisfy most of your different needs. Rustless & Durable: Made of high strength Carbon Steel with smooth nickel plating surface to extend the service life. Quick, Sharp & Smooth Cut: Coated with high quality Diamond to enhance the drilling speed and creates a sharp, high precision and smooth cut with no broken edges In Seconds. Application: Drill Glass, Tile Bottles, Blocks Jars, Fiberglass Porcelain Tile Ceramic, Slate Mable, Granite Light Stone.Not for use on Concrete or for depths beyond about 1/2". Attention: Please keep the speed in 800-1000 per minute, keep adding water to keep the drill cool, strictly prohibit from dry drilling. Diamond Drill Bit Set, 10 PCS Glass Hole Saw for Tiles Glass Ceramic Marble Bottles DIY,6mm -- 30mm Features: Good performance:diamond dust coating offers superior performance and cutting strength. Wide application of the Tile Hole Saw: coated core drill bit removes a complete circle from glass, tiles, marble, granite, ceramic or other materialsand only needs water for lubrication. 10 SIZES: No matter which size hole you want, it can always drill a perfect hole for you. Specifications: Material: high quality steel, diamond dust coating Color: Silver Size: 6 - 30mm / 0.23"-1.18" (6mm, 8mm, 10mm, 12mm, 15mm, 16mm, 18mm, 20mm, 22mm, 30mm ) Quantity: 10 pcs Note: If you smell burning, back off Either your speed is too high or the pressure you're applying is too much. You're drill bit should never be hot to the touch, not even warm. Slowest speed Always use lubrication (water) Minimum pressure Package Included: 10 x Tile Hole Saw Diamond Drill Bit Set, 10 PCS Glass Hole Saw for Tiles Glass Ceramic Marble Bottles DIY,6mm -- 30mm