CamelBak 2016 Circuit Hydration Vest The Circuit is a perfect versatile, lightweight and low-profile solution for long-distance running Antidote Reservoir features easy open/close cap, lightweight fillport, dryer arms, and low-profile design Key Vest Features: External fill, sweat-proof phone pocket, stretch overflow storage, reflectivity, fits 30"-46" chest Designed to carry water bottle, extra layer, nutrition, phone, keys CamelBak Got Your Bak Guarantee: If we build it, we'll Bak it with our lifetime guarantee