With Patek Philippe Extract from the Archives confirming production of the movement in 1901. It has been cased and finished for the Observatory Contest where it obtained a Grade A Rating Certificate on 12 January 1907. It was sold on 3 July 1907.
Pocket watches by Patek Philippe with Guillaume balance are generally found in openface cases. Hunting cased examples, such as the present watch, are rare. The balance staff of this watch is furthermore set with a diamond endstone instead of the more commonly used ruby endstone, a feature only found in movements of superior quality.
According to the registers of the Geneva Observatory, the watch was presented to the category A contest in 1906 and achieved 212.3 points and the mention "Honorable"; the rating certificate was mailed to Patek Philippe in January 1907. Its movement was adjusted by the renowned precision adjuster C. Batifolier.