Display, exhibit and preserve artwork, photographs, documents, etc. 11” x 14” mats have a window opening of 7½" x 9½" to display 8” x 10” images. 16” x 20” mats have a window opening of 10½" x 13½" to display 11” x 14” images. Each archival series mat kit includes bevel-cut, archival alpha-cellulose 1/16” thick mat board that is acid-free and lignin-free, 1/8” thick archival and acid-free foam core, and an archival polypropylene crystal clear envelope with self-adhesive closure. Meets all Library of Congress conservation standards. Single layer black mat.