This is a solid, sturdy mattress--I have no idea how they smooshed it down enough to ship it in such a small box! Although sure enough, once we opened it, it turned into a nice, heavy cotton mattress. Exactly what we were looking for--there was NO ODOR at all when we opened it. In fact, we felt comfortable with our son sleeping on it pretty much right after we opened it, which I would never do with a regular mattress. It's fairly firm, which is what we wanted. Extremely happy with our purchase. Great kids mattress.