Calibre 37.9

Notes

The 37.9 is a continuation of the project started with the 12.68Z to standardize and rationalize production across the range of Longines movements where all are made with a similar architecture, so that the company could more easily and cost effectively produce a larger number of movements. Originally, the pocket watch calibre of this new production paradigm was intended to be the 18.68Z from the series of time only round calibres 12.68Z, 10.68Z, and 8.68Z would be derived. However, there was discontent in the technical department with the size and thickness of the 18.68Z and it was decided in 1933 to create a smaller and thinner calibre, the 39.7, which would become the standard pocket calibre in the range. Some versions of this calibre would remain in production by Longines into the 1980s.