The Savage 7004469 ProMatte Acid Free White Core Mat is 11 x 14" with an 8 x 10" bevel-edged cut out. It's free of acid and lignin, making this product stable and will not break down over time, nor turn brown. ProMatte fits standard photographic and frame sizes. ProMattes are manufactured to exacting standards. Each mat is packaged in a clear-view ply bag to eliminate warping.