I was very reluctant to order sheets online because I am extremely picky about texture and thickness. After a lot of research, I took a chance on these sheets. I am very glad that I did! They are a thick flannel, perfect for winter in cold climates. Even after four washings they remain soft and do not pill. My only wish is that they were able to fit a thicker mattress. I think a 15 mattress would be fine, but it is very snug on an 18.