A. Lange & Söhne

• cal. L034.1 key winding movement, 62 jewels • white dial, applied baton indexes, subsidiary seconds, fan-form sector for power reserve at 3, date aperture • 18k pink gold case, push button for date adjustment at case band, sapphire crystal display back secured by 6 screws and key winding system at case back • case, dial and movement signed • with an 18k pink gold A. Lange & Söhne folding clasp

The movement in working condition at the time of cataloguing. The dial in very good condition. Case in very good condition with only a few minor surface hairlines to the bezel, shows only little signs of use. Overall in very good condition. * Please note that the movement has not tested for the accuracy of time or duration of the power reserve and may need service at the buyer's expense. Please note that Sotheby's does not guarantee the future working of the movement. **Please be advised that the bands on this watch are made of materials derived from endangered or otherwise protected species, please refer to important notices for further information.**
"In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. All dimensions in catalogue descriptions are approximate. Condition reports may not specify mechanical replacements or imperfections to the movement, case, dial, pendulum, separate base(s) or dome. Watches in water-resistant cases have been opened to examine movements but no warranties are made that the watches are currently water-resistant. Please note that we do not guarantee the authenticity of any individual component parts, such as wheels, hands, crowns, crystals, screws, bracelets and leather bands, since subsequent repairs and restoration work may have resulted in the replacement of original parts. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective, qualified opinion. Prospective buyers should also refer to any Important Notices regarding this sale, which are printed in the Sale Catalogue. In particular, please note it is the purchaser's responsibility to comply with any applicable import and export matters, particularly in relation to lots incorporating materials from endangered species.NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING A LOT, ALL LOTS ARE OFFERED AND SOLD AS IS" IN ACCORDANCE WITH THE CONDITIONS OF BUSINESS PRINTED IN THE SALE CATALOGUE."

**Please be advised that bands made of materials derived from endangered or otherwise protected species (i.e. alligator and crocodile) are not sold with the watches and are for display purposes only. We reserve the right to remove these bands prior to shipping."

Accompanied by an A. Lange & Söhne guarantee, instruction manual, square socket key and a presentation box.

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.