I purchased this as I have purchased 4" toppers from here before. Unfortunately, this one was only 2" of mem foam and 2" of foam base. The one I had previously were a true 4" of mem foam. This was my error as I didn't realize my old topper was not half and half. I just wanted to say to anyone looking for a true 4" topper, don't get this one. It is not the same comfort level and I am starting to have the back problems that I used to have before getting a topper. Will probably be looking for a new one somewhere else as it does not seem that overstock carries the true 4" ones anymore.