The Nathan 1.5 Liter Vapor Bladder gives you an easy way to carry your water on long runs. Nathan designed the bladder to fit snugly in a pack so you can run with your hands free. A high-flow bite valve, quick-release hose and large mouth make the bladder easy to use and clean. With a generous 1.5 liter capacity, you can fit as much water as you need for a full day on the trail.