Memory foam mattress toppers work in exactly the same way as a memory foam mattress, it's just a thinner layer that rests on top of your existing mattress. Memory foam gently moulds to your body, providing additional comfort and support. All our memory foam toppers come with a premium soft knit cover. Please note, depending on stock levels at the time you place your order, you may receive a higher quality cover than the one advertised. Our Reve and coolmax covers are soft and breathable allowing for better airflow compared to standard covers, preventing overheating and promoting an even more comfortable sleeping experience. We always strive to provide the best quality products to our customers, and when a higher quality cover is available, we will be happy to send it your way at no extra cost. - DS Living Essential 5cm Thick Memory Foam Mattress Topper in Off-White - Size: Super King