In less than 4 hours this mattress is all ready almost completely risen to the 12 inches it represents itself as.  This is the second large piece of furniture I have bought from Wayfair in the past 45 days.  I love them both.  And although the box was heavy, I (petite 62 year old woman) was able to open it, remove the.mactress  and open it up on the box frame, all by myself.  I love Wayfair and will continue to shop there in the future.