not as universal as you would suspect

The Nexus 4 is 9.1 mm thick according to the manufacturer, this is something else from the envelope. I am therefore assumed that the holder for mobile phones between 9-13mm ideal.
But is not it. The mount is adjustable only in width and not in depth. Despite envelope just any 13mm be achieved, thus shaking the device when changing tap (up / down) back and forth. If the price is not acceptable and unfortunately goes back again.