CamelBak designed the Circuit Hydration Vest for minimalist runners who don't want a big pack cramping their style. The included 1. 5L Antidote reservoir features CamelBak's easy drinking Big Bite valve, HydroGuard antimicrobial technology, and the easy to clean PureFlow tube. CamelBak equipped the vest with an air mesh back panel and vest straps for the ventilated breathability you crave on hot runs. There's also a sweat proof pocket for electronics, stretch overflow storage for energy snacks, and two water bottle pockets for those extra long runs.