The Advanced Research department at Patek Philippe is responsible for horological improvements and technical innovations. One of their important developments in recent years is the creation of silicium, forged using the ultra-modern DRIE (Deep Reactive Ion Etching) process. Previously, hair springs were crafted from carbon steel, a material that is susceptible to magnetism, oxidation or rust and temperature variations. Modern-day silicium contributes greatly to the precision that Patek Philippe prides itself on, as it has non-magnetic, non-oxidisation properties, reduced mass, is not affected by temperature and has reduced sensitivity as it is three times lighter than conventional springs.

Following in the footsteps of this range's previous references, silicium is used in the references 5250 (the present lot), 5350 and 5450. With the most current reference, the three most important components of the escapement - the hairspring, the balance wheel and the anchor or pallet fork - are now in silicium or Silinvar, as Patek Philippe has named it. With the use of the revolutionary Silinvar Spiromax spring, Patek Philippe has ventured one step closer to perfection - the spring is isochronous regardless of temperature, movement orientation or magnetic presence.

To the best of our knowledge, this lot has never been offered at auction and is fresh to the market