Product details:

Our 4-ply matboards are Acid-Free and feature a White Core. With a 22" x 28" overall size, these mats fit perfectly into 22" x 28" frames and are bevel cut to enhance your 20" x 24" photos. Actual mat opening size is 19.5" x 23.5" inches so that the mat may safely and securely house your 20" x 24" photo, artwork, needlepoint, sign, etc.