The Dornblueth & Sohn Calibre 99.2 M (Medium) is a modification of Dirk's Calibre 99.2. It features the same design, but packed into an eminently wearable 40 mm case. This may seem to be a small achievement, but in fact it is quite an engineering feat.
When designing the Calibre 99.2 and 99.2 M, Dirk drew from his experience creating the Calibre 99.0 and Calibre 99.1. Dirk's vision was to add a power reserve complication without making the movement "bulky". Dirk had studied a number of other power reserve complications, and noticed that most used an excessive number of wheels to achieve this function (eight to ten in most cases).
By using such a large number of wheels, the power reserve indicator itself became less accurate due to its inability to measure subtle changes in the tension of the mainspring.
Dirk's solution - design the power reserve module from scratch, and after many trials and tests, Dirk created a power reserve function with just three wheels, making it immediately responsive to winding
Additional features include an oversized analog sweep seconds display at 9 to perfectly balance the power reserve indicator. Everything is here - 3/4 plate, beveled edges, screw balance wheel, swan neck regulation, engraved balance cock, screwed gold chatons, and blued screws (by flame of course, including the slots).
And now the extras. The name "D. Dornblueth & Sohn, Kalbe i./S.A." is hand engraved and not machine engraved, a virtually rarity on any watch. And all of the decoration (Côtes de Genve and the sunray finish on the crown wheel and ratchet) are all done in-house, by hand.
You'll notice that the movement is rose gold in appearance - this process itself is elaborate. After cutting and polishing the plate, Dirk treats the surface to turn the metal a copper color. After all of the drilling and milling operations are complete, the movement itself is treated with rose gold to enhance the deep color.
The dial is coated in silver, and is matte finished with black applied (raised) Arabic numerals and Glashutte "railroad track" markings around both the dial and subdials.
This watch features a brushed and polished nickel-free steel case and the crown is signed D. Dornblueth. Power reserve is 50 hours.