I have been using it frequently for about a month now, for running, and it seems quite good. It fits tightly around the waist and can hold quite a few things. I usually put my phone and keys in it, and they stay in place without feeling like they will fall out. I have also used a 500ml water bottle in it, but during fast running, it feels like it moves up and down when it's full and placed on the back side. If it's placed in the front, it's okay. Overall, I am satisfied as it can hold a lot of things. It doesn't seem to have opened yet, and I hope it will maintain its size.