Camelbak Ultra 4

Our most versatile vest features expandable storage to accommodate gear for varying conditions and distances. It's got 2 liters of hydration capacity, a sweat-proof storage compartments for your keys and phone, and a stretch mesh pocket for gels or salt tabs. The external-fill feature also lets your refill your reservoir without removing it from the pack, so you can save time on the trail. Worried that the weather might turn on you* The stretch mesh compartment expands to hold an extra layer or two. Need more than 2 liters of water* Load up the chest pockets with two extra bottles. And with two sternum straps and a hook-and-loop adjustable harness, this pack stays put now matter how rough the terrain.