I am a contractor and need to install grab bars (3) in (2) private bathrooms, paper towel dispenser, toilet paper dispenser, mirror and another sanitation bin on all walls are ceramic. I haven't had any luck with the drill bits I bought from local hardware stores, I could never get them to drill (3) holes without burning through. I recently bought these drill bits because I had (4) 1/4" drill bits in the pack that I needed and I was hoping 4 would be enough. Now after drilling 56 holes in the ceramic walls, um to accommodate all my internals i still use the first drill bit. i drill slowly and have my assistant squirt water on the drill bit to keep it cool while I drill. this drill bit just went through the ceramic tile. can't say I did Will be ordering more for my next project because I still have a good used bit and (3) new ones.