Great middle ground between the longer WXP and the wider ILPS, so it fits almost any of my bags comfortably. I specifically got it to shove it alongside the BW folding sleeping mat in the 65l BW rucksack that's sold on Varusteleka and it fits perfectly in the same pocket along with the mat while full. The product itself is great, I got it without the UTA adapter and while I clearly see the utility of it, refilling the bladder without that dongle is still very easy. Depending on what your source of water is, you won't even have to take it out of the bag. I've heard people complain that Source valves take too much effort to suck water out of. I must be a great sucker because I didn't have that problem at all!