Unzen u10 hydra pack 10l vol unzen bags by shimano are specifically designed to power an aggressive off road riding style utliizing shimanos accu3d body hugging fit shimano shapes each part of the bag to create a fit that stays moulded to your back with no movement or loose straps the rider fit x harness positions the shoulder belts right at the centre of the pectoral muscles solving the restriction of movement caused by conventional shoulder straps it also eliminates the need for a waist b