Maintain a blistering cadence during grueling races and intense training efforts with the Ultimate Direction Marathon Hydration Vest. This streamlined hydration vest holds a two liter reservoir within its main compartment, and it also sports dual bottle holsters for greater hydration capacity during the longest runs of the season. Adjustable sternum straps support the pack so it won't jostle around at speed. Cool Wick Mono Mesh shoulder straps maintain exceptional breathability to reduce sweat build up. There's a zippered pocket large enough for the iPhone 6, which is especially handy if you're tracking your running stats with a GPS based app or listening to music. Plus, there's a front stretch pocket for storing your keys and cash.