Open Face Indoor 24"W x 36"H Satin Anodized Finish Aluminum Directory Changeable Letter Board Product dimensions are 24"W x 36"H Concealed mounting brackets 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. Accept all size letters from 5/16" to 3"