Prospective purchasers are advised that several countries prohibit the importation of property containing materials from endangered species, including but not limited to coral, ivory, tortoiseshell and crocodile. Accordingly, prospective purchasers should familiarize themselves with relevant customs regulations prior to bidding if they intend to import this lot into another country.
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. The silicium is used in the references 5250, 5350, 5450 & lately the new limited edition perpetual calendar 5550. With the two most current references, 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.