This pack borrows the ingenuity of our Atom but ups its carrying capacity and customizes the shape for a hydration pack. The streamlined, ultralight Hydrogen stays close to your body, whether you're on a bike, trail or street. It easily swings around to the front for quick access. Slip your gear into the larger compartment and your water unit into the stretch-mesh sleeve, which has an opening for the hose. The pack's elliptical shape sits comfortably behind your shoulder, sparing neck and lumbar some of the strain. Compression straps cinch down and stabilize the load. You can also use them to lash on a windbreaker. Stash your fishing license and pizza coupons in the zippered chest pocket. All zippers are water-resistant. Reflective trim adds visibility. Made in USA.Volume: 500 cu. in. (8 liters)