This is a comfortable large-capacity sports hydration water backpack with a 1-2L water bladder. The water pack backpack uses high-quality nylon material, which is lightweight, waterproof and wear-resistant. It can make your outdoor activities easier. The Hydration pack backpack has light reflection strips, an emergency whistle and anti-theft zipper which will reduce your unnecessary worries during the trip. It's is suitable for hiking, cycling, cycling, running, camping and many other outdoor activities.