I tested this support with an Iphone 5 S and an ATV that I mainly use road and path. It's really easy to install. Once in place, the phone fits easily and the screen is protected by a transparent supplied hulls. Under conditions of single use: road, track, it does not move a hair and thus can use the GPS function of the iPhone and calculate its average, distances and why not also use a cardio frequency-mêtre with the corresponding application and thus better manage its efforts. Obviously, phone calls are best managed if the device is in a pocket. If one borrows difficult mountain bike route type, I think it will remain retained despite vibrations, but I did not check. However, I am not on board electronics will appreciate that the violent vibrations. The same is needed with regard to sealing. During heavy rains the protection provided by the hull may be insufficient. So under normal conditions of use, this support is quite recommendable.