Deuter ventures into the purely hydration pack arena with the Hydro Lite Line. The Deuter Hydrolite 2.0 Hydration Pack is under a pound and gives just enough space for a few essentials. Water is the essential. The pack has a small front pocket for pump, tools, and semi-valuables. There's even a loop for a blinky light. Remember, this is a minimalist pack for the days when you want to schlep nothing other than water, and a few tools. You're not sticking clothing in here.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 shoulder straps are mesh. There is a sternum strap and hip belt for stability as well.Deuter has chosen not to make their own bladder, but use one from Source, an Israeli company. The Hydro Lite 2.0 get the Streamer 2.0 Reservoir. The Z-Valve is a plastic valve covered by a soft rubber cover that is leak-proof. Bite and the liquid flows. Let go, and the flow stops. It's that easy. There is a plastic cover that protects the valve, though many leave it in the car when riding. The reservoir itself is made from a BPA-free polyethylene (PE) plastic that boasts a surface as smooth as glass. Smooth is important because the smoother the surface, the harder it is for bacteria to attach. In addition, the surface makes it harder for taste, like old Cytomax, to remain after the bladder has been washed. Sealing the pouch is a bar-and-clip system that allows the bladder to be both opened completely and sealed completely, and is tough enough to be landed on without bursting.The Deuter Hydro Lite 2.0 Hydration Pack has 185 cubic inches (3 liters) of cargo capacity. It comes with a 2-liter reservoir insulated with Mylar, the same material as those reflective blankets passed out after marathons. Dimensions are 15 tall by 7 wide by 3 deep. There are two different grades of pack cloth utilized...