I use this Sport Armband for iPhone 4S for a few years and am generally very satisfied. Generally this bracelet is made of neoprene, has a viewing window made of plastic, through which can be operated with slightly elevated pressure the touch panel and has a Velcro closure. The main advantages in my opinion: + IPhone sits quite firmly, because the bag is very tight - slipping is thus virtually impossible, + Continuously adapt to the arm (would be strange if this were not the case) + A practical pocket for a key the only criticism I have is a lack of opportunity that may curling long headphone cable and stow. I solve this by I wrap the cable "to the Velcro", but a given solution would be more practical.
