The is a great addition to my new Osprey Transporter 40. It fits more than you would think. With the stretchy material on the sides, you can definitely stretch the load these things can carry. I like my packs to be organized and these little sacks help do the job. I have the 3L+ and I can fit a large size rain jacket in this sack. You should definitely check one of these out, especial with the great price! The quality is also fantastic, as expected from Osprey.