The viper 3 and integrated 3 litre hydraulics reservoir ensures that you can carry all the required gear and liquid to perform your best the reservoir is accessed via an asymmetric zip for quick and easy refills the reservoir incorporates a unique hydrostatic plate that maintains an anatomical shape but also keeps water pressure high for a smooth delivery of water osprey have also solved the wandering hose issue with competitors designs by placing a magnet on the sternum strap and bite valv