Pheidippides, the first dude to run 26. 2 miles, died after finishing the feat. As uninspiring as this may be, you can take comfort in the fact that he didn't have the CamelBak Marathoner Hydration Vest. Since hydration can mean the difference between life and death, CamelBak included a 70oz Antidote reservoir to provide up to two hours of death free running. From mid day trail running to torturing marathons, this vest won't bounce annoyingly behind you with every step its adjustable harness holds the pack to your torso tighter than a frightened spider monkey. At less than 11 ounces, you will barely notice the additional weight behind you. Because marathons are, well, sweaty, CamelBak stitched Air Mesh into the back panel for increased airflow. Store an energy bar, phone, and wallet in the pack's cargo pockets for on the go, quick and easy access. When cruising through the neighborhood at night, take confidence in the additional safety of reflective panels and a built in whistle. The Antidote reservoir is the industry's most popular solution to on the go hydration. At the turn of a cap a quarter turn to be exact, you can open or close the reservoir, refilling and securing it again in seconds. Center baffling and a sleek design prevent your water from jostling about inside your pack while running, hiking, or hitting the park. When not off exploring the world, simply disconnect the tube using the Quick Link System and hang up the Antidote for proper drying or storage. Since last year, CamelBak's go to reservoir system has actually lost some weight, reducing bulk in the fill port and offering you that much more convenience.