It is fascinating that you can add left and right game control buttons to my grandson's iPhone. They only work with certain games, but they work well. On the back of each button is an adjustment wheel to make sure they are mounted firmly, but not too firmly, to the phone's screen. Then you adjust the on-screen game controller buttons to match these new buttons. Now you can touch the top of each button and it acts very much like a Playstation PS4. They work great and don't cause any damage to the phone screen.