This bed topper came in a box, wrapped in plastic, upon taking it out of the plastic and laying it flat on our bed to air out and get to full size it took about 12 hours. It fits our california kind bed perfectly. We love how much comfort it adds to our bed and how well it seems to cool us down when sleeping on it. The bottom of the bed topper has a non slip grip and it seems to really help with it not slipping off the bed while we sleep.