First, the case is a little tight and it is difficult to insert the iPhone 4.
The "window" of this case allows navigation on the iPhone, which is very convenient.
The opening to insert the iPhone remains "gaping" once the iPhone inserted; it therefore poses sealing problems.
It is hard to imagine a jog in the rain with the cuff; which is a shame ... A small zippered or Velcro closure would not have been refused, history of well shut its iPhone to not fear the rain ...
Housing for a key seems too small also.
Ultimately, this armband is good, but not great. From Belkin, is expected to finish in every detail, and we are a little disappointed.