Whether you're hiking, biking, cycling, or simply exploring the great outdoors, staying hydrated is important. High Sierra had the adventurer in mind when designing this collection of hydration backpacks for on-the-go hydration. The HydraHike 2.0 4L Hydration Water Backpack can hold up to 4 liters of content and includes a 2-liter reservoir bladder. Use the top zipper to easily access the reservoir and main compartment to store other items like a jacket or sandwich in this backpack. For smaller items like keys, phones, or wallets this hydration pack features a front zippered pocket with an organizer built-in. Secure this backpack during high activity with the adjustable waist belt. To fill your 2-liter bladder, easily remove the Bpa-free reservoir from the main compartment, fill, and replace it. Bite down to take a drink, activating the on-off bite valve switch. Rest assured your water will not leak from the mouthpiece unless you are biting down on the valve.