original c. 1920's american vintage industrial single-sided porcelain enameled "elektrika" high voltage cautionary or danger sign. the sign was salvaged from the northwestern indiana steel mills. the graphical warning was made specifically for eastern european immigrants working in or around electrical equipment within industrial settings. features the universal skull & crossbones, along with fist grasping lightning bolts. rare and highly collectible. likely fabricated by the stonehouse sign co., denver, co.