Lightweight and Comfortable: This hydration backpack for hikers is made of army green polyester, which is stain-resistant, waterproof, durable, and scratch-resistant. The back panel of the backpack is softly padded to prevent chafing against the skin during sports. The adjustable shoulder straps fit closer to the back, making the backpack more comfortable, lighter, and freer during running, cycling, hiking, or other outdoor activities. Easy Hydration: The hidden Velcro pocket on the back of this 3L hydration backpack holds a 3L water bladder. A sufficiently large screw cap for filling water easily accommodates ice cubes and enough water to stay cool and leak-free, which is important for outdoor athletes to keep water cool for a long time, even in hot weather. Smart Design, Very Practical: The hose of this 3L water bladder comes out of the shoulder bag. Thanks to the smart design, you can refill water directly via the hose's bite valve without having to take off your backpack during running, cycling, hiking, and other activities, saving time and effort. Gift for an Adventurous Outdoor Activity: This backpack with a hydration bladder is suitable for all types of outdoor terrain. The small and lightweight hiking backpack is ideal for outdoor activities such as hiking, cycling, camping, running, music festivals, carnival, kayaking, etc. It suits everyone. This backpack is also a wonderful gift for friends and family!