"Needed to cut a couple of holes for a wall mounted tap through 9mm porcelain tiles. After a failed attempt with another drill bit this is the best money I ever spent. Don't get the impression the coating will last too long, but I got 6 holes out of it in just a few minutes. Only slight 'interesting' bit was getting started without it wandering. If you've got a lot of holes to do then maybe spend the extra on a good bit but this is perfect for a one off DIY job."