This pack is small (12L), but perfect for a day hike or climb. It holds my climbing shoes, chalk bag and harness no problem. I haven't tried out the hydration part, but I guess it works like a CamelPak. My only complaint so far would be that the shoulder straps aren't padded. But, I don't think that's too big of a deal since you can't really carry anything super heavy in such a small bag.
This review was written in the old system and had content requirements that are different than reviews written today.