I was thinking of a 4 star review but just thinking that I paid 3 pounds for that holder, I easily changed my mind to a 5 star.
On and Off setup at the air ventilation is not that simple but still gives a solid hold for a range of phones.
When you use small (thin to be precise) phones like Galaxy SII it looks quite bulky but the overall quality is outstanding.
There are definitely better holders out there but I doubt that you can find something similar for 3 pounds
I would highly recommend it for someone who uses the holder either occasionally or doesn't mind leaving the holder there permanent.