Insider: A. Lange & Söhne Lange 31. Equipped with an Outstanding 31-Day Power Reserve.

If you ever thought that an 8-day power reserve was impressive, the A. LAnge & Söhne Lange 31 ref. 130.025 is the first mechanical wristwatch with a power reserve of 31 days. Yes, this exceptional timepiece will run for a whole month when fully wound so that you can rotate timepieces in your collection as frequently as you want without losing a single beat or having to reset your calendar because your timepiece stopped while wearing other watches in your collection. 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 A. Lange & Söhne 31 is fitted with a solid silver 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 dial, perfectly well balanced is not only beautiful but extremely captivating.

The Case & Crown

Available in a generous case measuring 45.9 mm in diameter and 15.9 mm in thickness —in platinum as ref. 130.025 or in 18K rose gold as ref. 130.032—, 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

While the front of the timepiece is immaculate and pure perfection, the surprise behind the display case back is even greater. The beating heart inside the A. Lange & Söhne Lange 31 is the in-house manual wound calibre L034.1 composed of 406 parts, 62 jewels —three in screwed-in gold chatons—, lever escapement, shock-resistant screw balance, Nivarox balance spring with a frequency of 21,600 semi-oscillations per hour, whiplash precision index adjuster with patented constant-force escapement and stop-seconds mechanism for precise time setting.

As mentioned before the movement provides 31 days of power when fully wound. 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.

Just to put things in perspective about how amazing the L034.1 calibre is, there are 3.7 meters of mainspring in it. The energy is stored in the large twin mainspring barrel, which actually consists of two stacked barrels with an inside diameter of 25 millimeters.

Each of them accommodates a 1,850 mm long spring, which is up to ten times as long as in conventional mechanical wristwatches. When fully tensioned, the barrels store more than 3 joules of energy.

The longer the mainspring, the more noticeable the loss of torque as it relaxes. This loss affects the rate accuracy of the watch. 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.

The Strap

Fitted with a black matte alligator strap with deployant Lange buckle in matching metal, the watch wears comfortably but slightly high and ultra top heavy on the wrist due to its thickness and massive weight at 275 grams of pure goodness. The watch wears slightly bigger than its actual size and hard to wear for anyone with a wrist smaller than 7.25" in circumference.

On the Wrist & Pricing

If you are a Lange lover or just a mere watchlifestyler that appreciates the best of the best horological creations, the A. Lange & Söhne Lange 31 is a must have in any collection. This fascinating timepiece is not easy to source but if you are lucky you might be able to find one across the exclusive authorized dealer network carrying A. Lange & Söhne or by stopping by the recently opened A. Lange & Söhne boutique in New York City or Moscow.

Sticker Price $174,900 USD. For more info on A. Lange & Söhne click here.