Equipped with a 1.5 liter reservoir, the streamlined Osprey Seral 4 lumbar pack provides mountain bikers with a cycling-specific alternative to a traditional hydration pack. It has 244 cubic inches of storage, built-in tool organization, and a fit that ensures uninhibited maneuverability. The pack's Airscape backpanel has supportive ridged foam and a center channel that allows air to circulate effectively. The ventilated design combines with a mesh hipbelt to keep you cool and dry. The easy-to-use waist strap closure system means that you can get a snug fit, preserving your stability for riding or hiking. The zippered main compartment has a smaller internal zip pocket and built-in tool organization (tools not included). The pack also holds an included Hydraulics 1.5 liter lumbar reservoir. The horizontal design comfortably situates weight on your hips and a magnetic bite valve attachment keeps your hydration hose secured. Two zippered hipbelt pockets keep small items organized and easy to reach and an integrated blinker light attachment point (light not included) and reflectivity enhance safety and low-light visibility. The Osprey Seral 4 lumbar pack is available in your choice of colors.