The Deuter Hydrolite 2. 0 Hydration Pack is just over a pound and gives just enough space for a few essentials, namely water. The 2. 0 uses the Deuter Airstripes comfort system. Airstripes are two strips of vented foam pads that sit between the back and the pack, creating a channel for the spine and allowing sweat to evaporate through the pads. The breathable mesh shoulder straps with anti chafe pads lighten your load so you can go farther and stay in comfort. The insulated, Mylar lined main compartment houses the included reservoir, which holds 70 ounces of hydrating liquids. And there's another small, front zip pocket for valuables and an energy bar.