The Nathan 1.6 Liter Insulated Hydration Bladder keeps your water cool when your workout heats up. Nathan designed the low-profile running hydration bladder to keep your water close to your body so it doesn’t slosh as much when you pick up speed. A high-flow bite valve lets you drink a lot of water fast, while the easy-fill opening makes topping off a piece of cake. With lightweight insulation, the Nathan 1.6 Liter Insulated Hydration Bladder ensures you get a cool sip of water whenever you need it.