The ORANGE HARD SWITCH SHAPING BLOCK has a layer of Velcro hook on the top and bottom, so you can use your screen on one side of the block and sandpaper on the other side or any combination you want. You don't have to change paper or screen as often. A time saver right! This block is blown in a mold using Flexpad foam. NOT GLUED! So it's way stronger and stays flat.