Ultra-stable hands-free lumbar hydration system for ultra-runners and long-distance races. The 2L Antidote™ lumbar reservoir’s lower center of gravity means ultimate stability, freedom of movement and comfort over the long haul—even when you’re running low, thanks to dual lumbar compression. Adjustable dual sternum straps and shoulder harness ensures a snug, stable fit. Quick-stash mesh pocket on the back for a shed layer plus two cargo pockets on the front. Integrated safety whistle.