A. Lange & Söhne
- A FINE AND RARE PINK GOLD WRISTWATCH WITH 31-DAY POWER RESERVE AND DATE
CASE 190012 LANGE 31 CIRCA 2009
- pink gold
The A. Lange & Söhne Lange 31 is considered by collectors and scholars as a revolutionary piece. This reputation is due to its exceptional 31 days power reserve with a very complex winding system attesting the craftsmanship of the Manufacture. To store the impressive amount of energy, the Lange 31 features two mainspring barrels which are five to ten times longer than those found in conventional wristwatch movements.
Deriving from the "key technology" of historic pocket watches, Lange's engineers were able to wind springs with delicate components of an ordinary winding crown train. This leverage delivered by the key facilitates a transmission ratio that is unheard-of with a crown. A square socket key introduced through an aperture in the sapphire-crystal caseback thus delivers the energy to the spring barrels. Combining the two mainspring barrels energy, it is enough to hoist a 100-gram bar of Swiss chocolate spanning over 10 feet.