The history of electron microscope production in Czechoslovakia dates back to the 1950s when a team led by Armin Delong in Brno started to produce microscopes. One of the first successful microscopes was the Tesla BS 242 model, which won a gold medal at the EXPO 1958. During its 30-year existence, Tesla produced over 3,000 different models of microscopes which were exported to over 20 countries.