Sport Force Multi-Function Hydration Backpack, Green Perfect for those who hike, backpack, bicycle or just love being outdoors! The Multi-function Hydration Backpack features a specially designed 2 liter water bladder with an on/off valve to prevent leaking Eliminates the need to lug heavy bottles The Multi-function Hydration Backpack is equipped with adjustable straps and also serves as a durable backpack, complete with storage pockets to hold necessities such as snacks, keys, camera, phones and more The entire unit weighs less than 1 lb.