I wanted a sinner mattress cover then you can typically purchase. I purchased a Tempur-Pedic mattress cover fully expecting it to fit my tempurpedic king size mattress which it did not. Tempur-Pedic mattresses are thinner than normal but the mattress cover is manufactured to fit mattresses that are far thicker than the typical Tempur-Pedic mattress. Therefore, the cover fits loosely and is a pain in the neck.