This thing does not fold. It's a little more than 3 feet across. It has some kind of mesh-like surface, attached to the perimeter with some seriously beefy springs. The whole thing stands on short legs. You can buy a stabilizer bar for it, which I did not get because I felt that was just an invitation to lost teeth with a young child. Apparently, adults use this thing with the stabilizer bar to jog in place. I gave that a try. First, I would say that while I don't feel compelled to wear a bra on a treadmill (provided there aren't random strangers watching), even while jogging, boy, howdy, I need some support while rebounding. Second, it's a bit tricky to not get off center on this thing, and it isn't that far from the center to the edge. You definitely have to pay attention, at least at first. It is unclear whether this will turn out to be like the treadmill for R. (must always pay attention) or the treadmill for me (can safely zone out occasionally).
T. has had an interesting response to it. It is easy to redirect him from jumping on the bed or couch to jumping on the rebounder, at least today. (You never know what the future holds.) But he doesn't persist in bouncing on the rebounder as long as he does on the bed or couch. I have a theory on this. The way this thing affects my inner ear is dramatically different than the way jumping on a bed or other spring surface does. But I can't tell if that's because I still have a head cold. R. says it doesn't feel strange to him. It isn't a bad feeling, but it is wicked weird, and a little bit goes a long way. If T. shares this odd reaction, it may help explain why he quits fairly quickly. And if this satisfies whatever he's jonesing for when he's bouncing on the couch for 20 minutes, then I'd consider this an epic win.
I'll try to remember to post updates on this topic. The good news is, even if T. decides to avoid the rebounder, I'm going to get a ton of use out of it.