I ordered an Omnigrid mat and pretty quickly warped it
. So when I went looking for a new mat I ended up ordering an Alvin brand. I love it. It is much thicker than the Olfa/Omnigrid mats and looks about the same. It cost me 18.00 for the 18x24 size. I have also use MegaMat, and I am much more impressed with the Alvin. Gina