Nagra I – Where all started 69 years ago. NAGRA I – The very first prototype with clockwork motor and miniature tubes, appearing in 1951. Two were sold to Radio Genève. NAGRA II – The first production model, miniature tubes equipped, clockwork motor, which appeared in 1953. In 1953, in a new facility, Nagra began the production of the Nagra II (a Nagra I with the option to have an external modulometer (a type of VU meter) in the sidewall. Later the Nagra II was improved to the Nagra II b and in 1955, to the Nagra II c (a Nagra II with some improvements in electronics and using the first Nagra printed circuit).