Test it before each use. Ruined an iPhone. I tested it once, when I first got it.But be sure to test it first. Use a tissue or paper towel inside, seal it up, then dunk it in sink full of water to test it before you put your phone inside. Some of them leak
I always close mine up when it’s “overinflated”. When it’s closed, you can then squeeze it and see if it’s leaking at all. It helps to dunk it underwater while you squeeze - bubbles coming up are a dead giveaway that there’s a problem.Test it before each use. Ruined an iPhone. I tested it once, when I first got it.