c. 1930's vintage american industrial single-sided midwestern power substation "high voltage" cautionary or danger sign. likely fabricated by the ready made sign co, new york city, ny. the visually appealing sign features an ominous skull & crossbones flanked by zig-zag lighting bolts. the sign is comprised of heavy gauge die cut steel with original porcelain enameled finish largely intact. the bottom screw hole grommets are original to the sign. surface wear evident.