XLAB's Aqua Shot Calibrated Bottle has helped athletes win world championships and it'll help you perform your best, too. This unique, time-saving racing bottle has a high-flow squeeze valve and 4-ounce gradations so you can gauge your hydration. It's made of taste-free and safe BPA-free polyethylene with a fast-flow silicone valve that seals tight as soon as you stop squeezing. The valve is also not exposed to dust or contamination. This fine bottle is dishwasher top-shelf safe, can be used with carbonated beverages and is even shaped to fit better in bottle cages.