The thing has a serious (and ridiculous) design flaw. You know the sleeve on the shoulder strap for the hydration tube? Well, the zipper is on the outside of that shoulder strap, so that unzipping it requires reaching almost under your armpit, and then you need to pull the tube out away from your torso to drink. It's a pain to use even when wearing just a t-shirt, and when you have a few layers and a ski jacket on, drinking out of the thing was a real production. It's supposed to make hydration easier! If the zipper was just on the torso side of the shoulder strap, as opposed to the armpit side, it would work perfectly. I showed the design flaw to 2 friends, and both were equally as stunned that someone could design a pack this way. So, I used it for one day, but it's utterly useless.