1Diamond Coating: This diamond opening bit is diamond coated, which makes the bit harder and more incisive and increases the drilling speed of the bit. 2Ni Plated Surface: This diamond drill has a Ni plated surface for longer life and improved surface erosion resistance. 3With Clearance Hole: This diamond drill has a clearance hole which facilitates the entry of cooling water and the removal of chips from the hole, making the drilling process easier. 4Wide Application: This diamond open hole drill is suitable for drilling holes in glass, ceramics, ceramic, tiles, limestone, slate, marble, light stone and fibreglass. 5Easy To Install: This diamond drilling bit is very easy to install, you just need to fit the end that is connected to the hole for the punch.