Excellent Performance - Drill bits have a unique hollow design for clean drilling and fast chip removal. They can help you open a perfect hole without burrs and wobble. The tool is resistant to small incisions and has a high punching speed, which improves work efficiency and saves time and effort. Economy Set - This drilling tool set contains a total of 7 diamond hole saws. Length: 5 cm. Diameter: 10, 25, 40, 55, 70, 80, 100 mm. Tools of different sizes are available to meet your different drilling needs. They are ideal for working on materials such as glass. Application: They only need to be installed on a regular electric drill to work. When working, you should apply cooling water to your surfaces, starting at a 45 degree angle and then drilling vertically. Your force should be gentle, especially when drilling starts and drilling is completed. Multiple uses: Opening tools are ideal for fragile hard materials such as glass, tiles, marble and granite. They can be used for daily glass