Our acid-free Textured Cream matboards are 4-ply and feature a white core. With an overall size of 17x17, these mats with Square openings fit perfectly into 17x17 frames and are bevel cut to showcase your 13x13 photos. Actual mat opening size is 12.5x12.5 inches so that it may safely and securely house your 13x13 photo, artwork, needlepoint, sign, etc. This pack includes 1 Single Matboard. Proudly made in the USA by Country Art House!