After machining, every single movement component passes through or is finished by hand, and often decorated, though many will never be seen. (Perfection inside and out is just the Patek Philippe way.) ...
When it comes to Patek Philippe ... an automatic Advanced Research perpetual calendar movement. The major change on Calibre 240 Q Si is the presence of a Silinvar balance wheel.
Watchers of Patek Philippe have been waiting to see what would replace the blue-dialled ... Stern’s other requirement was that there had to be a new movement, which is the ‘Calibre 240 PS CI J LU ...