The Camelbak UnBottle magically turns any pack into a hydration pack! Simply slip the UnBottle into the back of your bag to create an integrated hydration system. The wide mouth makes it easy to refill and clean and is threaded for leak-proof outings. Plus, the UnBottle is fully insulated to keep liquid cold (or hot) for hours. Features: Liquid capacity: 100 ounces Included HydoLock valve controls the flow of water with just a flip of a switch. D-rings allow you to easily attach the UnBottle to the outside of your pack. Durable exterior is abrasion-resistant.