DMI Professional Grade Large Ultra-Lite Diamond Core Drill Bits (13"+)Our Professional Grade Core Drill Bits are made in the USA with high quality materials built to last. Our diamond core drill bits are designed for medium to hard aggregate and reinforced concrete. Made from high quality diamonds, our drill bits are built to get the job done. This beast of a drill is the type of drill for those projects where you need to cut out larger amounts of concrete. This drill comes in a variety of sizes to choose from, with