Don't just take it from us...
This works well! I have used it a couple times now for our trips. It stayed around my neck and was definitely splashed and submerged in water. My phone stayed dry and I was able to take pictures the whole time!
I have taken this to the water park two times already and I have not had any issues with it.
I was skeptical with this product but decided to try it. As suggested, I did test it first. I kept it in a bowl of water all night and the paper towel was still dry in the morning. I have been using it while in the pool and it has been wonderful.