I bought it in a smaller size, I start with 2, 3 cm flat and then appear on any irregular voltages drop very slowly air bubbles, and then the cat. Unable to reposition it tears. Yet, I asked a similar product there twenties over a large area without difficulty. It should probably keep it flat to press forward, but why not say it in the user guide? In short, an execrable product. If you have money to waste ... take the risk after all some reviews are positive.