Sure, you can bring along a handful of trail mix and hope it gives you the energy you need to crush your weekend long run, or you can bring along the Nathan TrailMix 12L Hydration Vest and have all the snacks, water, and layers you need to handle whatever the trail throws at you. Offering a solid amount of storage for such a compact pack, the TrailMix vest is made with lightweight, moisture-wicking materials to help keep you comfortable as you run, and features smart design elements to maximize your storage. An included two-liter hydration bladder offers hands-free hydration when you're cranking out quick miles in warmer weather, and two adjustable front pockets hold 22oz soft water flasks for additional water storage. The 12 liter roll-top compartment lets you stash added layers, gear, and food, while two large and stretchy rear pockets provide additional storage to keep rain shells and windbreakers within easy reach.