Throw enough food, water, and layers for a full day in the mountains in the Ultimate Adventure 4. 0 Hydration Vest and start exploring forgotten trails and remote ridgelines. This full-featured vest has plenty of pockets for multiple energy bars, water bottles, and even a burrito--just in case you get a hankering for a bean and cheese once you gain the summit. The large back compartment is big enough to stash a rain jacket in the vest, so you aren't stuck sprinting back to the car once it start to rain, and the Comfort Cinch system makes it easy to adjust the fit of the vest to match your torso while you're on the move.