If you need to cut holes in tile or granite these are great. We've remodeled our basement a bit every few years and fitted our bathroom without hole saws and it was a real chore breaking off the tiles to match the pipes. They allow you to have a smoother and nicer hole and require a lot less work. You must use them wet to avoid damaging the drill bit or splitting the tile as if you were using a tile cutter. I really like that it comes with instructions as it will help you get sharper, more precise cuts and all the bits seem to be of decent quality. We tested them on some unwanted tiles first and they worked great. I'm excited at how much easier it will be to renovate our laundry room once we start tiling there.