Submariner 5512 — Mk 1 Old Font Coronet · OCC Four Line

Among the earliest four-line dials, reading “Officially Certified ChronometerChronometerA watch or movement certified for timekeeping precision under a defined testing standard. The applicable certification depends on its maker and period; it is not the same as a chronograph.” instead of the usual “Superlative ChronometerChronometerA watch or movement certified for timekeeping precision under a defined testing standard. The applicable certification depends on its maker and period; it is not the same as a chronograph. Officially Certified”; compared to the OCC 1675 GMT of the same period.