Back in 2005 Patek Philippe presented a new watch of a new kind for this venerable brand !

The Patek Philippe Advanced Research reference 5250 was based on a 5146 annual calendar, with a little plus. A little something that that only you die-hard fans and only if you were high tech aficionados could spot and appreciate.

The reference 5250 was the first Patek Philippe watch to incorporate the first step towards the Patek Philippe watch of the future: an escape wheel made of Silinvar®, for a better reliability without lubrication. Suitbert Walter covered this in full: http://www.thepurists.net/patrons/members/wsw/ppforum/sil05/pp_technew.htm

After more than 900 days of use of these 5250 the result is said excellent by Patek Philippe: more than 75% of these watches have increased their amplitude. The remaining less than 25% have remained in the norm.

The watch was there:  http://www.network54.com/Forum/196053/message/1112696762/%2ANew+ltd-+Ed-+ref-+5250+-+Annual+Calendar+%2A

A first glance at the new 5450

Here is the full subject:  patek.watchprosite.com /