Save paper by using a time tested and reusable writing surface. Black chalk boards are the perfect size for school, office and home message centers. Works well for handwriting practice, working equations, brainstorming, and more. Rounded corners and smooth edges for safety and comfort. For use with white and color chalk and felt erasers. Hardboard backing is warp and chip resistant. Comes with adhesive squares for mounting. Measures 18" x 24" 0.125" For best results prime the chalkboard surface by rubbing the entire surface with the side of a chalk stick, then erase completely. Bundle of 3 Chalk Boards.