We purchased the single fitted sheet for our adjustable bed because it wasn't as deep as many sheets offered for sale. In the past we have had so much excess fabric that pools on the top of the mattress because our mattress is only 10.5 inches and so many sheets fit up to 18" mattresses. I was so tired of the excess and it seemed to get looser the more you slept on it. Right out of the dryer most are okay. These sheets stay much tighter than our old ones. The elastic on the corners is nice, but our main concern was the depth. They work wonderfully for us and we will be purchasing more in the future. Thank you for excellent product!!