I purchased the Serta 4 inch Memory Foam back in June after hearing from my sister how her memory foam bed gave her an uninterupted sleep. Well, my husband and I did not want to spend more money on an entire new bed, so we decided to give the foam mattress a try. We both do physical work all day, and needed a good nights rest. And we definitely have gotten it with that mattress! But after the first night we thought, wouldn't it be nice to find a cover for it. So I went back on to Overstock.com, and looked. At first found nothing, then only a down cover (wouldn't work because I have allergies). Then spotted in July the Down Alternative Cover! I was so happy, but then sad because it said it was for the 3 inch foam. But I thought, what the heck, I'll give it a shot. If it fit, great, if it didn't, I would return it. Because returning anything to Overstock is painless! So I bought it. It came, my husband and I put it on, and it fit perfectly! It also looks great, and we feel much better sleeping on it, rather than just on top of the mattress alone. It does not give off heat, infact, it actually reduced the heat. We love it! It was one of the best deals I've gotten on here! Now we both sleep soundly, with no pains, because it actually gives us further cushioning! We both highly recommend this product. Great cover, and an even better deal, price wise!