Longines Calibre “E”

European Watch, Clock and Jewellery Fair 1975 BF 213
A new development in mechanical wristwatches : Longines presents a
recently developed movement featuring two series-coupled coaxial barrels. This design allows an increase in the number of mainspring development coils to 17 (instead of a maximum of 10 in a standard watch) and very low motor torque. Since mechanical stress is less pronounced and there is less friction and strain, components and lubricants both last longer while performance and reliability are improved. Lastly, the watch gains in accuracy and durability. (LONGINES - “E” Calibre)