Soft, breathable, stretchy....
I sleep on a Temperpedic Grand Bed, snd it’s almost impossible to find sheets that don’t ride up the corners or move when I’m elevating the head or foot of the bed. 
These sheets stay put! And they are soft, cool, and comfy. I would definitely buy again. I just wish they were less expensive. Then I could buy 3-4 sets at a time.