I have had this mat for over a year and it was fantastic. Until it started to warp. It now has 3 large humps towards the outer edges. I tried weighing them down. Nothing. I tried gentle heat and then pressure. Nothing. I tried an industrial heat gun and then weighing it down but those jumps are still there. At this point it is unusable and I have to buy a new one. I will likely buy a different brand. Good for a while but not forever.