The Daxio is Camelbak's branching out into the student market. You have a few of options for hydration in this:1) Hands-Free AdapterJust use Camelbak's hands-free adapter for your Better Bottle that comes with the pack. You don't have to get your pack out, and water comes right to you. The downside is that .5L is really not much water.http://www.backcountry.com/store/CAM0263/CamelBak-Better-Bottle-Hands-Free-Adapter.html2) Camelbak ReservoirA Camelbak Hydrotanium Reservoir would in theory work well, but it has its own flaws. The reservoir is designed to go into the laptop sleeve, and while I've never had problems with a leaky reservoir, they can be floppy and a pain to work with. That being said, you can still easily get a 3L reservoir in there with some extra gear. No laptop.http://www.backcountry.com/store/CAM0158/CamelBak-Omega-HydroTanium-Hydration-Reservoir.html3) Camelbak Unbottle or StoawayHere's my favorite option. The Unbottle or Stoaway can be used in any pack, any time, doesn't really matter. It's a little more self-contained, etc.If you want to take the pack skiing or into the cold, the stoaway has a handy insulated tube to help with freezing. You can defeat the anti-freezing thing by just blowing water out of the hose and back into the reservoir though.http://www.backcountry.com/store/CAM0237/CamelBak-Unbottle-Hydration-Pack-3L.htmlhttp://www.backcountry.com/store/CAM0254/CamelBak-Stoaway-Hydration-Reservoir.html