The Calibre 400 Series is a clean-sheet design, developed from a blank page: we didn’t start from an existing base calibre. Apart from the obvious features like the five-day power reserve and the elevated anti-magnetism, a lot of thought and work went into making the movement more durable so we could recommend 10-year service intervals and guarantee it for 10 years. It took five years to develop the movement, including an extensive testing programme, and the result is a series of movements we’re confident will deliver years of high-performance timekeeping for today’s world citizen.