I was pleasantly surprised at the fit of this little hydration pack. The straps are ample with load lifters and a small waist strap. the bigger outside pocket has two mesh pockets and a key clip. I'm 5'11" 250lbs and I'm seriously thinking about using this for my daypack. it holds the bladder (or water bottles) and a rain coat well in the main pocket with smaller pockets for other basic gear, ie: headlamp, lighter, knife, first aid kit, etc.
It's not huge, you're not going to put a sleeping bag in there, but the size and weight makes a great short day hike pack.