When your main need is hydration, you need the High Sierra Wave 70 Outdoor Hydration Pack. The main compartment holds a 2 liter water reservoir that has an easy access opening for filling and also accepts most brands of water filters. A hands free reservoir pressure valve keeps your water pressure strong, and the insulated water tube cover prevents your water from freezing in the tube. A zippered front accessory pockets holds your small essentials like keys, wallet, or cell phone. The Vapel mesh AirFlow padded back wicks moisture away to keep your back cool and dry, and the Vapel mesh AirFlow adjustable shoulder straps are comfortable for the long haul. A reflective loop holds your bike's LED blinker so that you're seen in low light conditions.