Patek Philippe. An attractive and very rare 18K white gold limited edition automatic annual calendar wristwatch with sweep centre seconds, silicon escape wheel, power reserve indication, moon phases, original certificate and box

With Patek Philippe Certificate of Origin stamped Juwelier G.D. Wempe, Bremen and dated 6 March 2006, Advanced Research brochure, wooden presentation box and outer packaging.

Purchased by the present owner in 2006, this reference 5250 has never been offered at auction before.

Reference 5250 was launched in 2005 and made in a limited edition of only 100 examples in white gold.

Patek Philippe's Advanced Research department is dedicated to the research of new materials and components for watches. The department has achieved wide recognition for its efforts over the years and attracted much attention for innovative watch parts that contribute to improved rate accuracy and reliability. The creation of silicon (si), or silicium in French, for use in watches has been one of the department's most significant contributions to watchmaking. Patek Philippe used the technique to incorporate it in the making of watch components.

The new development of reference 5250 is based on the use of silicium or Silinvar as Patek Philippe likes to call it, including the Silinvar escape wheel which does not require lubrication.