Telephone openwire Lines are on the left with electric utility circuits on the right; note the latter's rather unusual insulator pins. These were made by the St. Louis Malleable Company in that city beginning around 1900. They were very well built and the Union Electric Company (St. Louis) used a very great many of them for decades. Most were clamped to the crossarm without the need of boring holes in the wood (that allegedly extended crossarm life according to the manufacturer). Municipal circuits for fire alarm and police call boxes are beneath. All sorts of glass insulators were used on the city's communications wires, notably CD 133 H.G. Co. varieties including earlier ones with smooth bases..