This very attractive and rare Rolex pocket watch is enhanced by its original and completely untouched four-tone dial. Furthermore, it is an officially tested chronometer which achieved “Classe A” rating after completing a rigorous observatory trial. The dial is inscribed “Controlée Officiellement” and the movement further inscribed “Chronomètre Classe A”. The most accurate watches made by Rolex in the 1930s were in fact the pocket watches which remained major sellers until the start of World War II. Various laboratories around the world were responsible for grading and testing watches, a standard Swiss chronometer test would last 15 days, the tests consisted in observation of the watch's timekeeping in various positions and at various temperatures, with points awarded for accuracy. Rolex used several different observatories for their testing, the nearest being Bienne, St. Imer, Neufchatel and Kew near London.