First introduced in 2019 as a base
link for the surprisingly lovely 5212A Weekly Calendar Patek also swapped the 26-330 into the Nautilus 5711 for the last couple years of its run. Its most important technical upgrade as compared to the 324 is the addition of a new second wheel that's made using LIGA and has long slotted
link teeth on each gear. This is meant to smooth the ticking of the seconds hand and prevent the backlash seen on other seconds
link hands.