After searching months for online 'bed in a box'--my main searches were for multiple comfort levels, no fiberglass, even expansion and no odors. The mattress rose to 9 inches upon opening and filled to 10 within 16hrs (but we gave it a good 24 hrs before finally settling in)Will be on the firm(er) side top-side up, but you will 'break' it in some to your idea of the firmness you are expecting. We had a $$ mattress after 5+ yrs that was starting to give us the aches and pains upon wakening, and the first night with this one, woke up pain free! Love the soft cover color!