I bought two (2) twin topper sets. The memory foam is about 2.5 inches thick and mattress topper about 1.5 inches thick. My daughters love them... In fact, they just returned from a trip with their Mom and told me they were very happy to get back in their own cozy-comfy beds. Another point - both my youngest daughters are very warm blooded. The foam seems to keep them much cooler at night. Overall, they no longer toss and turn, and they keep the covers on.