Travel and adventure are at the heart of Vacheron Constantin's Overseas collection, which moves into new terrain with the gradual introduction of complications such as this perpetual calendar in an ultra-thin skeletonised version. Such an exploit is made possible by Calibre 1120 QPSQ, a fully skeletonised automatic movement that measures just 4.05mm high. An NAC electrolytic treatment gives it a contemporary grey shade. The perpetual calendar with indications of day, date, month and leap year is joined by a moon-phase display, in a pleasing symmetrical layout on the dial. Like all Overseas watches, this model in 18k gold benefits from an interchangeable strap system, meaning the integrated gold bracelet can be swapped out and replaced with a leather or rubber strap for maximum versatility.