@newnew Yea the flagship REI store is right in downtown Seattle so hit that up if you can it's a pretty cool, huge store. There are a bunch of different CamelBak backpacks that you can find at REI or online that are various sizes and come with a reservoir. The one I have is called the Mule and it has a lot of different pockets and compartments to put all sorts of stuff. There is usually a main padded compartment specially made for the reservoir that has a slit for the tube to go through. It fits a surprising amount of random items for its size even while holding a 3L reservoir. So yea the pack is for holding/insulating the reservoir and also for holding whatever else you want. Hope that helps, good luck buying man.
Board - 2012 Burton Restricted Easy Livin' Flying V 158
Bindings - 2012 Burton Cartels