I install TVs and always hated having to install them on tile or stone because I felt all of the drill bits I'd use were not working as expected. It would take 20 minutes to make one hole. I purchased three different kinds of tile and 4 different drill bits and tested them all out. These are beyond my favourite. I've used them on two jobs now and they take about a minute to go through stone. I don't know how long they'll last but even if I have to purchase them for every three jobs I don't care.