OVERALL SIZE (Made to fit a Frame Size Measuring) 26x26 Inches | Bevel Cut Square Opening Size of 20.5x20.5 inches | For a Photo Measuring 21x21 Inches. THIS IS FOR 1 single matboard. White PHOTO MAT with a square bevel cut opening. A great way to change up the look of an existing frame with a new accent mat board. This matte also works great as a replacement for damaged, dirty, or faded matting in your old frames. PREMIUM QUALITY: Our precut photo matboards are acid free & precision cut with a 45 degree bevel by machine for perfect corners and NO over-cuts every single time! All of our precut matboards are MANUFACTURED BY POSTER PALOOZA IN THE USA.