Unfortunately for me the sticky surface to be in contact with the disc was poorly made. This has probably a fold in the bearing surface formed during production or in storage. This allowed air to penetrate into the small vacuum chamber and the holder did not stop. With a little creativity and an old rubber pad for the phone I was able to fill the fold and it now holds. The construction is stable and the rubber linings hold the phone reliably. My Z1 with sleeve fits with its 76mm fits loosely into it. Unfortunately, the internal mechanism vibrates when it is fully open but that you can also avoid by it closes slightly.