Description -4 pc's Dry diamond drill bits with hex shank. -Sizes: 1/4'' (6mm), 5/16'' (8mm), 3/8'' (10mm), 1/2'' (12mm) -For hole drilling on porcelain, ceramic, granite, marble, masonry, and various types of tile and stone. -Vacuum brazed diamond technology provides fast, chip-free holes while maintaining a long life. -Quick change hex shank provides better chuck grip and fits different styles of drills. -Fits different styles of drills. -Drill bits are integrated with wax. Allows for self-cooling and dry drilling (water may be added for longer life on harder stones). WE AIM TO SURPASS EXPECTATIONS We are so confident in the quality of our product that we back every purchase. Whatever the reason, contact us and we'll make it right!