PLEASE READ WHY: 2 part review, first is the waist pack. I've run with hydration vests, handhelds, and waist packs, and this is my go to for anything that just requires 20oz. The pocket size is perfect for a couple gels and a key, and the way the bottle sits is very easy to access. Very well done. Second is the bottle: the kicker valve is good, the bottle size is right, the loop catch is great. Mine won't stop leaking. I get home from a run and my bottom is covered in water. I honestly didn't care in the heat of the summer, but now that it's winter I've had to retire it. Fix the bottle or just get one that doesn't leak and you've got a 5 star product. UPDATE: UD's customer service is great. They contacted me to make sure I was still happy with the pack and offered a bottle replacement. There's no other company out there offering that kind of service. I've updated my star rating to 5 stars because the issue was simply a faulty bottle, which has been resolved.