late 1920's antique american industrial surface-mount heavy cast bronze metal single-sided chicago loft building service elevator cab or car "call" push button plaque designed and fabricated by or for the otis elevator company, new york city, ny. the square-shaped rectangular-shaped plaque contains a single circular-shaped opening with a black composite or bakelite button above the words "call elevator." the diminutive elevator call button box retains the original interior components housed in a black enameled cast iron casing. great overall condition with a nicely aged surface patina. measures 2 1/2 x 2 1/4 x 4 inches.