Ben Fowler wrote an answer about Burton Wheelie Locker on February 16, 2012
It's a little bit of both. You can basically fold the bag in half when it's empty, but that's it. It's like a preformed shell on the backside of the bag with the exception of the center where it can be folded. It's a pretty durable bag. I own a previous years 166 model and have traveled with it at least the last 2 years. My only complaint (which is actually brought up in ultrakenji's review) is that the bag is too stinking heavy. I packed 2 Boards(159 Ride Concept UL, and a 153 GNU DK) a jacket, 3 pair of pants, my helmet, spine protector and impact shorts and was already at the 50 pound weight limit. This last trip was a pain trying to pack things in my other bag because this bag was maxed as far as weight. It's got a ton of space you can't use unless you wanna pay for overweight bags when you fly. If you're road tripping with it then that's another story, but for flying cross country, I don't plan on using this bag again because it weighs way too much. Hopefully this helps.