Rugged tactical Cordura Nylon. Key features include: One large main compartment. One outside pocket with inside mesh accessory pockets.Hydration pocket with Velcro® closure and carrying handle; complete with 2.5 liter bladder. modular attachment points on front face. Expandable design and stay-coolmesh backing.Fully adjustable shoulder straps.Heavy duty zippers and hardware. Fully expandable. Size: 17" x 8" x 5"