I had my doubts
I've been running for a while now, not too long, but long enough to have a few half marathons behind me and a full coming up quick. While I was training for my halfs I would make it 14 miles without a drink. The thought of an 18+ training run without a drink didn't thrill me so I bought this worried about carrying weight and whether it would bounce around. I did notice it at first but the longer I wore it the less I realized it was there. The bottles are easily accessable and store quickly. It doesn't hold much, but enough to keep off full dehydration.