iPhone 5 Car Mount

A friend had an iPhone 4S car cradle (iPhone 4 mount + arm) and after buying an iPhone 5, asked if I could make a new mount for his iPhone 5 which would retrofit onto the arm of his existing cradle. I think that made sense. Anyway, this is the outcome. The iPhone 5 mount is based on jbobrow's case (http://www.thingiverse.com/thing:31026) and has been modified at the base to fit onto a car mounting arm. I personally don't have an iPhone 5 but presumably the case fits fine. Not sure how generic th