Our acid-free Dark Purple matboards are 4-ply and feature a white core. With an overall size of 20x20, these mats with Circle openings fit perfectly into 20x20 frames and are bevel cut to showcase your 16x16 photos. Actual mat opening size is 15.5x15.5 inches so that it may safely and securely house your 16x16 photo, artwork, needlepoint, sign, etc. This pack includes 1 Single Matboard. Proudly made in the USA by Country Art House!