I have the 4 bottle belt with the 8.5 oz bottles. I love it. The belt is a stretchy 2" wide belt that closes with velcro. I've used it on runs up to 10 miles. Since the belt is stretchy, it doesn't bounce around. The wider belt doesn't cut into you like a narrower one might. The bottles are easy to get in and out. I've found the bottles pretty easy to use. The tops close off realiably so you don't end up splashing yourself as you run. I'm going to use my belt on my next tri. I need a lot of fluids and I've never mastered running and drinking from those little cups they hand out.