My phone keeps slipping out of the controller because nothing is stopping it. *Update* In response to this lack, I put my phone all the way in and marked the spot on the bottom of the phone, then drilled small holes in both grips and actually used one of the parts from the Battleship game to stick in there so my phone wouldn't slipped. Just thought I'd share and upvote as it wasn't hard to fix. Otherwise it's a great controller.