14 Sizes Diamond Coated Hole Saw Drill Bit: 3mm/5mm/6mm/8mm/10mm/12mm/16mm/18mm/20mm/30mm/40mm/50/mm/60mm/70mm. Good quality diamond drilling tool set, meet your different needs. Attention: Reduced drill speeds, best to control within 800-1000 per minute. Water is required for lubrication when drilling. Low drill pressure and increased use of water lubrication will extend drill bit life considerably. Durable: These diamond drill bits are high quality, good performance and processed for a smooth and exact finish. Excellent for making clean and accurate hole on glass and tile. CREATES A HIGH PRECISION: Coated with high quality diamond, the diamond hole saw creates a high precision holes in Seconds. Smooth cut with no broken edges. IDEAL FOR: This diamond coated core drill bit removes a complete circle from glass, tiles, granite, marble, ceramic and so on. Create a high precision, smooth cut. Also coulld be applied to plastic sheeting, wood and other products.