This hydration pack backpack is made of durable polyester. A carrying backpack with 3L water bladder for your outdoor activities, like running, hiking, climbing, cycling, biking.Breathable padded shoulder strap and mesh back panel is extremely comfortable and lightweight, which will release heat rather than accumulate, keep your back dry. 1 horizontal strap surrounding your waist can firm this hydration backpack on your back. 1 year warranty on every backpack. Comes with a built-in 3 Liter hydration bladder. It's made of TPU material, and the 39 inch length straw is long enough to drink without any pressure. Simple and convenient for you to drink water. 1 main compartment is for storing 3L water reservoir. Another two large pockets inner can store your tablet, books, clothes, towels, umbrellas, etc. 3 front pockets are designed for you to access some frequent used items conveniently, such as your phone, wallet, paper, keys, cables, powerbank and other small items. Made of durable and scratchproof polyester material with gliding smoothly zippers. Webbing throughout whole bag can attach additional pouch or outdoor gear. Suitable for outdoor sports, hiking, hunting, cycling, camping, running or training. Dimension: 17.32 x 11.69 x 3.75 inch / L x W x H. This hydration pack backpack can store your carry-on supplies, such as towels, umbrellas, sleeping bags, water bottle and so on.