In 1951, Stefan Kudelski built Nagra tape recorder, which was later used in film, radio and television. Kudelski conducted experiments at his home laboratory only in his spare time because the technical university faculty labs did not have the appropriate equipment. It was in this laboratory where the first model of Nagra tape recorder was built. Kudelski was continuously perfecting its product. The transistor version of Nagra III built in 1957 became the technological sensation in the sixties. This was the main type of tape recorder used by radio and television reporters and by film studios around the world. Kudelski received four awards of the American Film Academy for his tape recorder - two science and technology awards (1965, 1977) and two Oscars for his achievements.