I got this pack for day hikes and biking and its perfect size for my needs. I wanted a pack I could fit a sleeping bag and a lightweight tent in for an overnight hike and this pack can do it. I am 150# and 5' 10" athletic build and got the M/L and on the smallest setting it seems to be right where it needs to for a comfortable fit. I can't say enough for this pack it is one of the most feature loaded day packs I have ever seen and without the weight. This pack is plenty big for me to take on a weekend hike and will fit all my gear no problem, keep in mind its all ultralight gear though. Osprey out did themselves on this pack; I love the sleeping bag compartment because I can unzip the panel between it and the main compartment and my tent fits great in the bag. This pack also has a fantastic high visibility rain cover built into a compartment on the bottom of the bag.