Carl Zeiss is one of the world's oldest companies in the optics industry. In 1902, Carl Zeiss expanded into Austria-Hungary when a sales and service centre was built in Vienna. During the First World War, priority was given to producing war material, including gun sights for the Austro-Hungarian Navy. In the Military History Institute Prague collections is a gun sight produced in the Carl Zeiss factory in Vienna for the 15cm L/40 ship's gun. With a range of 10 kilometres, these cannons formed the secondary armament on the S.M.S. ships of the Habsburg, Sankt Georg, Kaiser-Karl VI and Kaiser Franz Josef I classes. It is also worth mentioning that these cannons were manufactured in the Skoda factory in Pilsen. The 148 cm long gun sight was coupled to this gun and has a magnification of five to twelve times.