One of the buttons didnt work on my 5s phone. It was recognized a software bug.
You can use Movie Pro with the Watershot Underwater Housing for iPhone 5/5S and it works great.
Movie Pro is a much better product, so use that instead.
For stills just use the iphone picture app. Its easy to switch between the two.
D_Ivanovich about Watershot for iPhone, v1.6.16