We purchased a firm mattress set from Overstock and the mattress was a little TOO firm for us. We purchased this gel memory foam topper in hopes that we wouldn't have to replace the mattresses and buy something a little less firm. It worked! It has totally changed how we sleep, and it doesn't hold your body heat. It also saved us a TON of money, since we didn't have to buy another mattress. I would highly recommend this topper, as well as Overstock. They accidentally sent the wrong product at first, but were totally professional, and courteous and sent the proper topper. We are completely satisfied and very happy! It's really thick (5 inches), but our old sheets were fine; we didn't have to purchase the "deep pocket" sheets just to fit on the bed. Very happy!