We bought a new Tempur-Pedic bed and had trouble getting our old fitted sheets to stay in place. The corner pockets weren't quite deep enough. Most mornings we'd wake up and the fitted sheet had come loose from the corner and bunched up. We ended up buying these directly from Tempur-Pedic and they're great for several reasons. Number one, they fit. Nice deep pockets. Number two, they have elastic straps that slip under the mattress to reinforce the hold on the corners. They do not come loose. Number three, the straps are color-coded so you can put them on a king-sized mattress correctly on your first try. No guess work. Number four, they're very comfortable. Good weight, soft, breathable. We'll keep buying these for as long as we own Tempur-Pedic beds.