Prepare for intense marathons like the Hardrock 100 withwell, with a lot of training first, but also with the Nathan VaporCloud Hydration Vest. Dual stabilization and load lifter systems utilize two dual sternum straps that compresses the included 2 liter bladder and the rest of your gear close to your body in order to provide a stable ride throughout the race. Wall mesh shoulder straps bring a lot of breathability to help keep your shoulders sweat free in warmer weather, and the insulated reservoir pocket prevents your warm body from heating up your liquids. The 2 liter bladder features a locking bite valve for easy drinking that doesn't drench you with water like other valves can. The VaporShadow has multiple zippered compartments and stretch mesh stash pockets to keep you well organized on the trail. The hidden internal back pocket is perfect for ice packs to help keep you cool, and Nathan designed its front bottle pocket to fit its 22 ounce Tru Flex bottle or any smaller bottle. The pack also has a zippered pocket for smartphones, a pocket for pills like electrolytes to keep you moving, and clips for trekking poles in case you need them on the trail. The external shock cord at the rear keeps everything compressed throughout the race so the pack feels tight from the moment you start the race until you finish.