Bought this so I could mount my iphone to my bike and use a GPS/Strava while riding, as I didn't want to buy an expensive GPS unit. The phone fits very securely inside, and it did not come loose at all. The fastening of the handlebar clip though did start coming loose, and had to be tightened every time I went down a rocky descent, but it was only on the really rough stuff. For my road bike where there is less reverberation from the road/trail surface it will be absolutely fine. Love that the case is waterproof and protects the phone if it does fall off.