I bought this for a friend training for his first marathon. He was constantly struggling with hydration and this ended up being just what he needed. It is nice having three bottles as you can take just the amount of bottles/water you need for your particular run. Bottles fit securely in their holders but are easily removed when you need a drink.
I have tried a lot of hydration belts and there always seems to be a problem with the design- the bottles leak, fall out of the belt, pocket too small to fit a phone etc. Not this one. Functions perfectly and is very comfortable. Perfect for long runs in the summer.