High Sierra Rush 2-Liter Hydration Pack (Cypress Black) Daypack includes a two-liter water bladder with a hands-free, bite pressure valve Shoulder straps are made of aerated Vapel mesh-Airflow material Comfortable back also includes two large padded sections of Vapel mesh-Airflow material Front organizer pocket holds bicycle tools, keys, maps, and other travel accessories Measures 17.5 by 10 by 4.5 inches; capacity is 885 cubic inches