I needed to install a shower door on ceramic tile and used a 1/4 bit and I was afraid it wouldn't last long enough but I did was able to drill 10 holes and a couple of them were over a piece of tile that looked like glass and didn't break the glass. I think the last few holes were a bit more difficult to drill and some of the material got stuck in the hollow part of the drill bit which probably made drilling difficult. But I'm really glad they worked and I didn't spend a fortune. I would recommend them. I have yet to install another shower door on ceramic tile with a 5/16 drill bit. I will update this review if another drill bit doesn't work properly, but for the price and the number of drill bits I got I think it's already paid for itself. BY THE WAY. I sprayed the tile with water and tried to wet the drill as much as possible.