I recently purchased a different memory foam mattress Woot offered a while back but I keep reading about these things!! I came across this particular mattress during my search for one and it took me a while to figure out that the top 4" layer only has 2" of memory foam: 1" on top, 1" on the bottom. The other 2" is some other type of foam. I wanted a mattress with 4" of memory foam and almost bought this one. The specs are listed in a little more detail here:
http://www.kohls.com/product/prd-c33416/pure-rest-12-in-reversible-memory-foam-mattress.jsp
Good luck in your search for a good night sleep. It can be tricky buying a bed online but my strategy was to go with a firm mattress so that I could try different toppers until I found the perfect combination. I ended up adding a 2" natural latex topper, which cost a bunch ($279 for 2" queen with cover). The combination of 2" soft latex over 4" firm memory foam works perfectly for my large frame. Way better than the $1800 memory foam mattress it replaced.
