Beneath its deceptively peaceful surface, Mt. Unzen in southern Japan hides the awesome explosive power of a volcano. It was the hidden primal force of this mountain that inspired Shimano to create the Unzen hydration pack collection. With no excess straps or bulk to hold you back, Unzen bags are specfically designed to power an aggressive off road riding style. After installing you hydration system, just throw in your tools and favorite energy bar. Fasten the Rider Fix X Harness and head for the hills. The body hugging fit of Shimano's Accu3D technology frees you to follow the path less cycled. So if you're ready to unleash your own hidden power, try Unzen by Shimano.STRETCHABLE BODY Thanks to the unique stretchable main fabric, the backpack is expandable without the use of extra fasteners that add unnecessary weight and bulk. The aerodynamic 3D stetchable body makes sure the wind flows smoothly over the pack while riding at high speeds. NO LOOSE STRAPS We made sure that our ACCU3D hydration packs have no loose straps anywhere. The only straps that are necessary to adjust the harness have a storage pocket to make sure they are invisible to the wind. EASY SIDE ACCESS No need to take your pack completely off when you need to access your things fast. FELT LINED VALUABLE POCKET To safely store your valuable items without scratching them, this pocket has a soft felt liner. The bright color helps you locate your things easily.