The Steady Betty is not a pressing sheet. It is a board covered in thin foam, not fabric. The fabric will not move when pressing. It is quality made, reversible, and heavier then it looks. I use it to press all my quilt pieces and blocks. If you can find the foam backed vinyl (use to be sold as outdoor fabric) you can make your own. I found some but the price of the fabric was as much as buying the board. Here is video of the small size one being used and described:
https://www.youtube.com/watch?v=0HZ7VYosv2w