More water or aerodynamic advantage? You used to have to choose, but with the Vision Drink System, you can have your cake and eat it too. It's a super-cool system made just for time trialists and triathletes. It gives you the ability to put two different drinks in one hydration unit and comes in a handy aero design to help you cheat the wind. Which is pretty darn awesome if you think about it.
Buy Vision Aerobar Drink System from Chain Reaction Cycles, the worlds largest online bicycle store.