Disadvantage:
1) To paste the pellet (the largest for a smartphone) that has a protective cover, it is mandatory that it be type "GLOSSY" (Brillante) if you have a matte cover (rubber) of the pellet strong chance to ignore.
2) Once the Frête fixed to the gate, the latter blocks the ventilation circuit mode "closed circuit", which translates into a noise pat blocked blades.
3) If your smartphone is a bit "heavy" it tends to move the ventilation grid down slightly and thus disrupt the viewing angle of your smartphone, Not always handy in GPS mode ...
Apart from these three inconveniences that this system very practical day to day, especially for the GPS mode of your smartphone.