Never go thirsty with the Osprey Viper 9 Hydration Pack on your back. Designed with the cyclist in mind, it is also good for light and fast hikes where minimal kit, well stashed make for swift ascents. Comfy, well ventilated easily adjusted back system. Ample 2.5 litre reservoir for all day fluid requirements. Side compression straps keep the load stable and minimise bulk, whilst your kit can be easily kept in order by the series of internal mesh pockets.