The first picture is the flat sheet from Sleep Number that I was planning to replace with these SGI sheets listed on Amazon. I held it up with the window in the background. The second picture is the flat sheet from this set of SGI sheets also held up to the window. Notice the difference?These SGI sheets are advertised as 1000 thread count which means the number of vertical and horizontal threads per square inch is supposed to be 1000. The Sleep Number sheets in the second picture have a 600 thread count. Does the sheet in second picture where you can actually see the outline of the window look like it has more threads per square inch than the sheet in the first picture? Not even close. Egyptian cotton? Why would I believe they are Egyptian cotton if they lied about the thread count?I threw these SGI sheets in a box and sent them back. Do not order them. They are junk.