I purchased this to put on my daughters older mattress. It is so thick you fall into it!! It is 4 inches of pure foam! She was having trouble sleeping on the bed with the old "egg crate" style topper. I put this on and she wouldn't get up!!! It is well worth the money and works great. As I have noticed on other reviews, it is a little short for the queen bed. Not enough to say not to buy it...but just an observation.