original hard to find and highly sought after early american antique industrial "danger" porcelain enameled cold-rolled steel sign designed and fabricated by the industrial products company, philadelphia, pa. the manufacturer markings identifying the company are found on the lower right hand corner. the reinforced sign contains a nicely aged surface patina from prolonged exposure to a factory work environment. the sign was mounted against a door containing high voltage electrical equipment used to power the plant or factory. the sign contains multiple screw holes with steel grommets for mounting purposes. the factory sign dates to to 1921-1925. 14 x 10 inches