It arrives folded lengthwise (X3) then rolled. I gently unrolled it, left it to start expanding 20min, then very gently unfolded onto the thin fabric backing it comes with. Less than an hour later, it fully expanded to what you see here. My son (11) and I both sunk into it decently but not so much I sunk through all 2" of it to touch the floor. When we placed it on the mattress, I was surprised that it (Twin) seemed to be about 1-2" wider and longer overall. I was thrilled that it's full edge-to-edge coverage of the Mattress (Serta plush 10" deep) and also happy that it came with a large enough fabric backing that it was not in direct contact with my floor. I also bought a bamboo-quilted mattress topper/pad that comes in a few days but I expect he will like the new feel. He didn't like how firm it was before this. Minimal smell, but it didn't smell bad in any case. More like fabric softener to me. With the vent holes and gel infusion, I'm hoping it's cooler than my modern Temperpedic topper.
