Featuring a new easy-adjust system for faster on and off transitions, the Nathan HPL #020 backpack is built to handle your longest, toughest runs. With 2 liters of hydration, a repositioned bladder tube now exits from the top to eliminate skin contact for greater comfort in motion. Be prepared for every challenge with two zippered rear compartments that hold all your necessary nutrition and gear. Wall mesh shoulder straps and back panel facilitate air flow, keeping you cool and dry. 3-way Propulsion Harness moves with your shoulders and back to reduce wasted energy.