I bought an Olfa mat last year (summer). I placed it in the back of my SUV and drove home. It was hot when I took it out of my car and I put it on my table. It cooled off fine - then the next morning one side of it was warped. I took it back to JoAnn Fabrics but they wouldn't take it and said that they had problems with most of the Olfa's. I can't afford to buy another one as I am on disablility. I have really needed a good large mat, as quilting is therapy for me since my mother, one of my sisters', a nephew, and a brother-in-law died last year. My mother was a great quilter and it is comforting to me.