CamelBak's Circuit running vest is one of their more popular models- and it just got upgraded. It is now 30% lighter, and includes a new Crux reservoir that delivers 20% more water per sip than other reservoirs. Some of the features that make it a favorite of long distance marathoners and ultrarunners are front storage pockets for storing energy gels, zippered security pocket for your phone, and reflective accents to keep you visible in low light conditions. Two fully adjustable sternum straps will guarantee your run stays sleek and bounce-free, and will never restrict your breathing or movement.