Mardingtop Hydration Pack Mini Running Backpack MATERIAL- Polyester ,Water-resistant Polyester as the fabric do not allow water to easily penetrate. CAPACITY- 15L (915 cube inches); Hydration Bcakpack for cycling, hiking,running and climbing, designed to be comfortable and functionally versatile. FRONT ZIPPED POCKET- includes organizer for tools, camera, keys, maps, and other items. DETACHABLE WAIST-BELT- Adjustable and detachable waist-belt can easily remove with velcro straps. HYDRATION SYSTEM COMPATIBLE- Internal hydration bladder's compartment and on the top for the water tube outlet . Big engugh for 2 liters hydration bladder. (Hydration bladder not included).