SIZE: 41cm*29cm*10cm Durable MaterialThe material of the hiking backpack is high-density waterproof Nylon, good ventilation, no deformation, super versatile, and multi-functional. Leak-proof Water BladderA switch valve and a cover cap make double leak-proof. Hands-free hydration hose with suck mouthpiece, gently biting to get the liquid to flow. The large opening makes it easy to add ice cubes, clean and dry. With this BPA-Free, taste-free, and odorless hydration bladder, you can keep hydrated and active all day throughout your adventure. Hydration Bladder CompartmentThere is a compartment in the main pocket designed for putting Hydration Bladder, keeping you hydrated for a day. A great travel backpack for various sports activities, such as climbing, hiking, camping, backpacking, traveling, etc. The backpack contains reflective strips, which make you safer to walk at night.