Our acid-free Black matboards are 4-ply and feature a white core. With an overall size of 6x9, these mats with Oval openings fit perfectly into 6x9 frames and are bevel cut to showcase your 4x6 photos. Actual mat opening size is 3.5x5.5 inches so that it may safely and securely house your 4x6 photo, artwork, needlepoint, sign, etc. This pack includes 1 Single Matboard. Proudly made in the USA by Country Art House!