This thing is horrible DO NOT BUY send me half your money instead if you just want to throw some money away. I love the concept but the quality of the plastic used doesn't make this thing durable. The connection between the mount and the stem does not remain airtight. Worst of all, the nut that goes on the ball joint to tighten the clamp that holds the phone is not securely fastened. As a result, everything has to be adjusted and tightened again and again over the course of a 10 km journey. I also had to glue a screw to the adjustment lever that connects the phone mount to the mirror mount. Again great concept but bad design. I had to glue everything so the joints could be stabilized. It works a little, but it can be adjusted if necessary. There is probably another solution.