Light, works well
I wore this during sonkran in Thailand, which is a big water festival. I was drenched head to toe with buckets of water and water guns for about 6 hours, and my phone and money stayed dry. I haven't tested this with full immersion while swimming, so that's the biggest caveat to this review.
There are 3 mechanisms that keep water out. The top is heavy duty, and folded over twice with velcro. This is what I have been used to in previous dry bags that I've used for Kayaking. There is also a double zip-lock seal on the inside, and then inside of that there is another plastic transparent zip-lock style bag. I opened and closed it several times to get to items during the day, and it was pretty easy to re-create a good seal. Overall it seems to do its job!
Verified purchase: YesCondition: New