c. 1940's "new old stock" american vintage industrial cautionary high voltage sign manufactured by the ready made sign company, new york city, ny. the single-sided sign retains the original polychrome baked enameled finish over heavy gauge steel. standard voltages in the united states have to be 440 volts so that if a distribution transformer is used, 254 volts could be easily obtained by getting line to neutral voltages. the rounded-edge sign contains holes on each corner for mounting flush against a flat surface. measures 7 x 10 inches.