This mattress comes compressed and rolled up in a box. Once the plastic seal is broken, the mattress immediately begins to fill with air and take shape. Instructions say to wait 72 hours for it to fully form. Mine never really flattened out. It remains a bit wavy from being rolled so tightly. The firmness of the bed is perfect if I sleep alone and in the middle. It's firm but also soft. However, if my spouse lies too close, it's like I roll into a trench his body weight creates and he's under 200lbs. I also cant sleep or sit near edges because there's no support there. It just gives way and I slide off. (I'm 135lbs) Overall, its a decent mattress for the price but I wish I had spent a little more and got something better.