In 1950 Tavannes Cyma co launched a brand new calibre 454 series. It might not have been as lavashly decorated as it’s predecessor calibre 414, but it had some very cool features like the balance cock/bridge and capped escape wheel pivots. Cyma also used this calibre in the later Watersport models and the new Navystar models.
The most desirable of the variants must be calibre: 455 that featured a triple date complication.