These drill bits were bought to drill into brick. The first stone took over 30 minutes to drill a 1.25 inch deep hole with a hammer drill. The tip of the second stone broke after about 1/2 inch (see picture). I then bought a Bosch Diamond Ground Carbide Tip masonry drill bit and it was done in less than 20 seconds. As such, I would not recommend these drill bits for drilling into brick. Very disappointed with the quality and finish of these bits.