I bought two for my boyfriend (iPhone 7 Plus) and myself (iPhone 7) and they fit perfectly. We could even add some money notes or a credit card inside if needed. We’ve tested them for 2 hours in a sink and they worked, then we’ve used them for 3 weeks in the Philippines and never had a drop of water inside ! We’ve been snorkelling and canyonering (jumping from 5m high waterfalls) with them, and they never failed us.
The only downside in my opinion is that it’s hard to make photos/videos with it. As the tactile screen doesn’t work anymore under water, you have to use the side sound buttons but they don’t always work under water (because of the pressure I reckon). Also, the plastic layer in front of the camera tends to blur all of your pictures/videos. So if you want good quality under water images, you should better buy a Go Pro :)
First time using the waterproof pouch and I fell off my kayak. I had the supplied lanyard around my neck and my mobile (cell) phone in the pouch. The pouch worked perfectly and kept my mobile (cell) phone dry and safe. Very happy with my purchase.