Our acid-free Baby Blue matboards are 4-ply and feature a white core. With an overall size of 20x24, these mats with Oval openings fit perfectly into 20x24 frames and are bevel cut to showcase your 16x20 photos. Actual mat opening size is 15.5x19.5 inches so that it may safely and securely house your 16x20 photo, artwork, needlepoint, sign, etc. This pack includes 1 Single Matboard. Proudly made in the USA by Country Art House!