Having previously bought a Serta 4" memory foam topper (which was, indeed, 4" full inches of memory foam) for about the same price from Overstock, I did not read the "fine print" on this product and assumed I was getting the same thing again. WRONG! It is MISLEADINGLY NAMED. It is NOT 4" OF MEMORY FOAM, but rather, as the description does say, 1.5" of memory foam on top of 2.5" of traditional foam. DISAPPOINTED!!! On the plus side, it does seem to improve the situation of the mattress on which it was placed. Time will tell (have not yet slept on it) whether it works as well as the other topper. Caveat emptor...buyer beware...and read the full description.