I have one chirp cache and it is a puzzle cache. It was very easy to program and it has gone through a pretty heavy storm without any issues. It is attached with velcro so I am pretty sure it really is water tight given the rains we have had lately. So far the feedback has been positive. I have gone out twice with cachers that do not have a GPS that supports chirps in order to help them find it. I hope that the iPhone app is coming soon.