The general theme of modularity and customization that characterizes the new overseas models continues here, using the interchangeable strap system Vacheron developed and introduced in the 2016 Overseas models.  We’ve got a bracelet, leather strap, or rubber strap; both case and bracelet are in 18k white gold.  There’s a soft iron inner ring, to give protection against magnetic fields, and visible through the caseback is VC caliber 1120 QP (“QP” standing for quantième perpétuel, the French for perpetual calendar).  This is an extremely thin movement, as you might know; the base caliber was at its introduction in the late 1960s the thinnest full-rotor self-winding movement in the world, and remarkably enough, it still is.  The addition of an in-house developed perpetual calendar module leaves us with a movement only 4.05mm thick, and the watch overall is 41.5mm x 8.1mm – carrying the Hallmark of Geneva (also known as the Geneva Seal) as well.