The additional button at 8 advances the subsidiary zonetime dial (at the regular Lange 1's subsidiary seconds hand) and the city dial by an hour each push. Normally, when one is at home, the larger dial displays the home time, and the smaller dial is used to show time at a foreign location - useful for making phone calls internationally. Very similar to the JLC Master GMT, and not very useful for travel.
Here's the interesting Lange twist. The mechanism is made in such a way that the time displayed on the two dials can be easily switched, by pushing a button and correcting with the crown, so that the main dial and date shows the user's foreign time, and the subsidiary dial can be set to indicate home time, or any other location. Nice Lange twist! This is the reason for the dual day/night indicators. More details to be released after embargo is lifted!
The watch is now in caliber L031.1, with 417 parts, 54 jewels (one more than the regular 1), in a case 41.9mm diameter in either pink gold, yellow gold or platinum.
Marvellous year for Lange!
