I just got the BoB trailer and was trying to figure out a way to cram the HUUUUUUUUUUUUGE dry sak bag into my backback, and it worked! The bag can compress down to a really small size so I can use it to haul my gear to work, take the gear out and then compress the yellow sak into a small wad and put it in my backpack. I can't see leaving that thing out with the spider bungee.