These sheets work really well for my new Sleep Number P6 Split King with FlexFit 2 Base. The fitted sheets stay in place when going from flat to zero gravity and back to flat. The pockets of the fitted sheets are deep and fit snuggly around the mattresses. Also, these sheets are soooo soft. I typically don't use a top sheet, but these sheets feel so amazing that I have actually been using it. Love these sheets and will buy again.