The clamp works pretty well, depending upon the size of your cell phone and whether it's in a case or not. But you do have to be very careful how you touch the sides of your phone while it's in the clamp, and the phone has to be perfectly centered within the clamp, or it will slip out and fall to the ground. This happened to me twice the first time I used it. I started to return it, but then realized that if I am just more careful about centering it, and how I use the phone while it's in the clamp, it will hold. But it's not ideal.