Designed to keep you moving this 4L Hydration Vest is lightweight, breathable and features tapered back panels to keep the moisture out. The back is longer to help disperse capacity and thoughtful storage features include Kangaroo pockets allowing one side entry access point and a vertical pocket for larger items like trekking poles. Two front water-resistant pockets for phone and a pill pocket complete with whistle. A large diagonal zipper and size pockets allow for easy access. Hydration features two 20oz hydrapak soft flasks with our signature ExoSpine for stability and long hose and mouthpiece for efficient access.