Guinea pig
Very rickety and it tends to get stuck on itself when you fold it up. However, I've only used it indoors, which means the bars at the bottom often come loose because the rods between the sections keep popping up—maybe it works better if you can push the rods a bit into the lawn. I wish there was some way to keep the rods in place on hard surfaces, like a little cap or something. But it was a cheap purchase. I bought two at the same time and put them together to make an indoor pen.