− | Also in 1929 the [[Columbus Extra]] line was introduced, using the new filling system. Since then the name ''Columbus Extra'' was used to indicate the high-end production, so under this name were produced a wide variety of different models. Typically all models were further identified by a numerical or literal code. This line, with the same name and the same model numbers, remained in production for about a decade, while undergoing many stylistic and technical changes. Therefore is very difficult to classify with the same name a production that can be highly differentiated. | + | Also in [[1929]] the [[Columbus Extra]] line was introduced, using the new filling system. Since then the name ''Columbus Extra'' was used to indicate the high-end production, so under this name were produced a wide variety of different models. Typically all models were further identified by a numerical or literal code. This line, with the same name and the same model numbers, remained in production for about a decade, while undergoing many stylistic and technical changes. Therefore is very difficult to classify with the same name a production that can be highly differentiated. |