I'm selling this as I've moved up to a larger size Osprey.
This is the original model which enables you to hang a bladder in the air space between your back and the body of the sack.I'm including a 2 litre Platypus bladder.
Like all Ospreys the actual capacity is generous. I've used it for summer walking. As I recall there's a review on the OM site. Colour is grey and black (looks blue in one of my photos!)
Note that the bottom corners have a small amount of the fabric of the bag rubbed away and I've covered these with gaffer tape. You can see this on the photos here:
