The Lange 31 with an amazing 31 day power reserve! One of the most challenging aspects in production of mechanical wristwatches is the duration of the Power Reserve, understandably the longer the Power Reserve the more convenient it is to the wearer. Thus most top brands invest considerable time, effort & funds into developing a mechanism that can store the most amount of energy within the constraints of a wristwatch case size. Storing energy within the constraints of a wristwatch case size is only half of the challenge. Mainspring torque fluctuation (especially in watches with larger power reserves) will have a negative impact on accuracy. Thus an equally challenging feat is transferring the stored energy from the mainspring to the movement in a controlled and uniform manner.
Enter the LANGE 31 with a power reserve of 31 days and a patented constant-force escapement. The double stacked mainspring barrels, each with an impressive 185cm long spring, store the energy. A constant-force escapement situated between the mainspring-barrels and the going-train assures that the balance receives an identical amount of energy every ten seconds, regardless of the state of wind of the springs.
Another practical feature is the Key Winding Mechanism rather than winding via the crown (which would require many winds & stress the crown stem) the watch is wound using a provided key that fits into a matching aperture on the case (sealed with 3 gaskets to ensure water resistance). The provided key has a built-in torque sensor, once the watch is almost fully wound the key senses the increase in tension & will disengage the ratchet key.
Case: Polished & brushed 18kt white gold case. Grey colored dial. Polished white gold hands. Applied polished index hour markers. Fine printed minute track. Small seconds sub-dial at 6 o’clock. Large double-window date at 10 o’clock, with a corrector button on the case edge. Over-sized 31 day power reserve indicator on the right side of the dial.
Strap: Fitted on its original dark brown alligator leather strap with a solid 18kt white gold deployant buckle. The strap is in near perfect condition with most of its life-span remaining, we would be comfortable rating the strap at 98% condition.
Movement: Powered by a Lange & Sohne in-house calibre L034.1. Comprised of 406 components, contains 61 ruby jewels & 1 transparent sapphire jewel (total of 62 jewels), beats at 21,600 vph, and has an impressive power reserve of 31 days (744 hours). The movement three-quarter plate is decorated with a fine ribbing pattern and features blued steel screws.
Condition: In immaculate near brand new condition. Our customer purchased this watch roughly 3 weeks prior to trading it into as he found the watch too large for his wrist. The watch was worn a handful of times at most. We would be comfortable rating the watch at 98%+ condition. Delivered in its original box with all papers.
Watch Features: Big Date, Power Reserve Indicator
All Papers Warranty dated 05/2019
Time remaining, expires: 05/2020
18kt White Gold
Scratch Resistant Sapphire
Pre-owned A. Lange & Sohne Lange 31 White Gold Limited 130.039 130.039F