The Anneks Waterproof Phone Case is extremely nice to have around and more useful than most people would even think. I do not go out on a boat or swim often but when I do I will be sure to take this case with me simply for piece of mind.
To initially test the case I stuffed it full of paper towels and submerged it in water for a half hour. After removing the case and drying off the outside I opened it. The paper towels on the inside were completely dry. Next I put my phone in the case and submerged it. All functions seemed to work just fine except for of course the fingerprint sensor. I was unable to test the rated 20m certification the packaging boasts, but my phone survived being fully submerged numerous times for extended periods.
If you are looking for a waterproof case for piece of mind while fishing or hunting, to swim with, or run in the rain, or whatever other reason, I highly recommend the Anneks Waterproof case which can be found here.