PREMIUM QUALITY: These diamond drill bits that made of diamond and carbon steel with durability and rust resistance are wear-resistant and sharp. DESIGN: 85mm The side slots can help the entry of cooling water and the ejecting of debris from the borehole. SMOOTH CUT: Coated with high quality diamond to ensures smooth punching and makes the drilling process easier, precise cutting and no rough edges. WIDE APPLICATIONS: Can be used for ceramic, marble tile, stone, glass, diamond coating and other hard material. KINDLY NOTE: Please keep the speed in 800-1000 per minute, keep adding water to keep the drill cool, strictly prohibit from dry drilling., Weight: 0.0 Pounds, Manufacturer: Dapetz