Our acid-free White matboards are 4-ply and feature a white core. With an overall size of 32x32, these mats with Square openings fit perfectly into 32x32 frames and are bevel cut to showcase your 28x28 photos. Actual mat opening size is 27.5x27.5 inches so that it may safely and securely house your 28x28 photo, artwork, needlepoint, sign, etc. This pack includes 1 Single Matboard. Proudly made in the USA by Country Art House!