As you’ve probably seen across social media and blogs this morning, German watchmaker A. Lange & Söhne unveiled a new “Lumen” version of their famed manually wound flyback chronograph.

The Datograph Up/Down Lumen comes in a 41 mm x 13.4 mm platinum case and is limited to 200 numbered pieces. It’s the fourth model in the Lumen series that started in 2010. And like the past timepieces in the series, it has a special coating on the semi-transparent sapphire-crystal dial that filters out most of the visible light, but not that part of the UV spectrum which is needed to charge the luminous pigments with light energy.

There is a lot of luminous material on this watch. The hour and minute hands are lume filled. The centrally mounted chronograph seconds hand is fully coated with a luminous material. The small seconds and chronograph minutes counter are both completely luminous. Even the outermost chapter ring, which has the minutes gradations and tachymeter scale, glows green. As does the power reserve indicator arrow. Lastly, the patented oversized date function has been made completely luminous, which is especially tricky because the design allows light to charge the numeral discs even when they are hidden under the tinted sapphire dial.

Most interestingly, the date discs can be viewed through the dial, in a dark room, as the date is changed by pressing the corrector at 10 o’clock, which is the marquee feature of this watch compared to say a regular Datograph. And you’ll, of course, pay a significant premium for such illumination (a pre-owned Datograph in platinum without the lume can be had for less than half the price).

Underneath the hood is the legendary manually wound 2.5Hz, 454 component caliber L951.7, which has 46 jewels, 4 screwed gold chatons, and 60-hours of power reserve.

Retail is $100,500 and it’s available for purchase now.