Amazon has cutting mats marketed for architects, for way less money than the ones marketed to quilters. I took a chance and bought one. Mine is 24”x36”, but is not the largest I found there. Mine is two sided, which I love (who doesn’t like two for one?). It is so much better than the old blue plastic one I had. When I bought mine I had a choice of black with green reverse, or blue with pink on the back. I have the blue and pink.