Nathan X-Treme 3-Liter 900-Cubic-Inch Hydration Pack Rapid Access bladder pocket 900 cubic inch capacity, weighs 20 oz. 3 liter Hydration Bladder with a Slideseal top closure and bite valve Tube routing and clip Zippered main compartment, expandable stash pocket, and small zippered compartment Honeycomb Mesh shoulder straps and back panel add comfort, prevent chafing, and dissipate heat