6100 cu in, 100 liters. At 7 lbs 8 ozs it's not a lightweight, but it's amazingly comfortable fully loaded. Conforms to the body and distributes weight comfortably.

Sizing: Waist belt and shoulder straps are medium. Pack body is labeled small. I remember years ago being fitted for this at Eastern Mountain Sports. I'm always a medium, but at the time, this Denali Pro in a medium torso was oddly too big (mislabeled? manufacturer slip-up?). They reconfigured a small torso with the medium shoulder and waist. My torso is 19" which is a definite medium. Nonetheless, this pack as configured has been a perfect fit. See photo of me in green shorts. I'm 5'8" and 150. the hip belt is exactly where it should be, about one inch above top of hip bones. That confirms this pack fits like a medium should. If you're much bigger, like someone who recently tried it at 5'10" and 180 lbs, I wouldn't recommend it.

Shoulder straps and hip belt positions adjustable.

Top lid converts to day pack - very handy after hauling all your gear to base camp. Bottom access. Lots of features to mount skis & gear. There's nothing you can't put in or attached to this pack. Gregory produced this pack for years while the rest of their line and other makers started downsizing packs. It may be the only big sturdy hauler around at this time. It's getting harder to find expedition packs. New ones are not as durable. They save a little weight but mainly by flimsier fabric, no fanny pack and smaller volume.

With more than a dozen other backpacks, I finally am thinning out garage and admitting I won't be doing this kind of traveling anymore as much as I hate to get rid of it.

Here are a couple links for more info and photos:
http://gregorypacks.com/en/GM68738.html
http://www.amazon.com/Gregory-Denali-Pro-Mountaineering-Pack/dp/B001EPPJB0
http://www.backcountry.com/gregory-denali-pro-backpack-6450-cu-in

New this cost $550 or more. Selling mine in excellent condition - no damage and totally clean and good looking. For $99 + shipping, about $20 USPS or $30 UPS to mid-USA.

Thanks, James