For nearly a decade, the A. Lange & Söhne Lange 31 has been the first and only mechanical wristwatch with a power reserve of 31 days and a patented constant-force escapement that continuously delivers uniform torque. Last week at the SIHH 2017 in Geneva, A. Lange & Söhne unveiled a new variation of the Lange 31 —up until now only available in platinum as ref. 130.025 or in 18K rose gold as ref. 130.032— in 18K white gold with a grey dial. This new watch is limited to 100 watches. If you ever thought that an 8-day power reserve was impressive, the A. Lange & Söhne Lange 31 is the first mechanical wristwatch with a power reserve of 31 days. Additionally, the A. Lange & Söhne Lange 31 it features a patented constant-force escapement, which makes it possible for the first time to actually harness such an extreme power reserve. This mechanism assures high rate stability and thus consistent rate accuracy for an entire month.

The Dial

The new A. Lange & Söhne 31 in 18K white gold is fitted with a classic grey dial with its unmistakable matte granular finish, the iconic oversized date aperture at 10, a subsidiary seconds register at 6 and its stunning 31-day power reserve indicator in all its grandeur between 2 and 4 o'clock.

The Case & Crown

Available in a very generous case measuring 45.9 mm in diameter and 15.9 mm in thickness, the case band features alternating satin brushed and highly polished areas with the traditional date adjustment pusher at 10 o'clock and a signed A. Lange & Söhne winding crown.

The Movement

Powered by the same calibre as the other Lange 31 references, the beating heart inside the A. Lange & Söhne Lange 31 in 18K white gold is the in-house manual wound calibre L034.1 composed of 406 parts and 62 jewels. Just to put things in perspective, there are 3.7 meters of mainspring divided in two coupled barrels with an inside diameter of 25 millimeters. Each of these barrels accommodates a mainspring that is 1.85 meters long —up to ten times as long as the mainspring in conventional mechanical wristwatches.

Due to its impressive power reserve, to fully wind the watch, A. Lange & Söhne provides a small key that fits in the small circular opening located to the left of the main plate to complete the operation. The longer the mainspring, the more noticeable the loss of torque as it relaxes. This loss affects the rate accuracy of the watch, because of that, the constant-force escapement of the Lange 31 re-tensions a remontoir spring by 60 degrees every ten seconds to assure that a uniform amount of torque is delivered across the entire power reserve period.

On the Wrist & Pricing

If you are a Lange lover, the A. Lange & Söhne Lange 31 is a must have in any collection. By far, one of the most impressive watches released by A. Lange & Söhne this year at the SIHH 2017. While the platinum and 18K rose gold versions of this watch are ultra special and good looking, this new iteration is our second favorite after the platinum one.

Sticker Price €142,300 Euros —approximately $152,000 USD. For more info on A. Lange & Söhne click here.