SOG Opcon Hydration Day Pack with 2-Liter Reservoir, 18.2-Liter Storage Military-style backpack with included 2-liter hydration reservoir, tubing, and easy-to-use bite valve for on-the-go H2O Carries comfortably on your shoulders with yoke-style adjustable, padded straps and adjustable sternum slider; adjustable webbed waist belt for added security Large main compartment and a smaller secondary compartment, front accessory pocket with organizer, and top front zippered accessory pocket Tactical features include MOLLE webbing for attaching a variety of optional accessories; hook-and-loop are on front of pack for attaching a flag patch; Measures 17.3 x 9.2 x 6.9 inches (WxHxD) with 18.2-liter capacity; backed by lifetime manufacturers warranty