Enclosed Indoor 36"x24" One Door Grey Aluminum Radius Design Directory Changeable Letter Board Product dimensions are 24"W x 36"H. The fixed rear panel is a felt cover letter board designed to accommodate changeable letters with tabs spaced on 1/4" centers. Includes a set of 165 count - 3/4" Helvetica letters. Standard features include: acrylic safety glass windows, continuous hinges, concealed mounting brackets, a black felt background, and locking doors.