Mid Century brass letter slot with a nickel finish. Inscribed DM565. The spring load slot opens 45 degrees to allow mail through. The Penn Hardware company became known worldwide as quality manufacturers of door knobs and locks, exporting their products to Europe from the late 1800s through till 1950s. The exact date of creation is unknown. The dimensions are Outside 11 in. L x 3.75 in. W, inside 8 in. L x 2 in. W, center to center 10 in.