Specification: Item Type: Hole Opener Color: gold Material: diamond Size: 6.5 x 6 mm Hole diameter: 6 mm Usage: Suitable for drilling holes in marble, concrete, granite, ceramic tile, glass, etc. Package List: 20 x hole opener Note: 1. The hole opener is installed on the electric hand drill. Since this hole opener does not have a drill for center positioning, work carefully and be careful about safety. 2. Continuous addition of water for cool, dry drilling is strictly prohibited. Otherwise, friction will occur at high temperatures, which will lead to serious wear and tear and deteriorate the effect of use.