At 9 o’clock, you have the sub-dial that indicates the day, and now at 3 o’clock you have the sub-dials that reveal that the date and power reserve. At 6 o’clock, there’s a month indicator and moon phase screen, and to the left of it at about 8 o’clock you’ve the entire year indicator. Finally, there’s the flying tourbillon that makes a single turning every minute at 12 o’clock. The motion within is your self-winding Iwc Watches Atlanta grade 51950, which is based upon the Caliber 51900 found in IWC’s additional tourbillon watches like the Portugieser Tourbillon Mystère Rétrograde but with the ingenious 82-part endless calendar module manufactured by Kurt Klaus. This motion also contains IWC’s Pellaton winding system also contains a generous power reserve of 168 hours, or seven days. It is visible through a sapphire display caseback and features a unique commemorative 18k gold rotor.The other tourbillon watch that IWC has specially prepared for its 150th anniversary is your Portugieser Constant-Force Tourbillon Edition “150 Years.” This comes at a slightly larger 46mm wide Portugieser design case and is only accessible platinum. Like the sooner Portugieser Perpetual Calendar Tourbillon Edition “150 decades,” this watch also has heat-treated blue hour and minute hands. This is an upgraded version of previous Constant-Force Tourbillon watches — Portugieser along with other versions — combined with all the “perpetual moon phase display. At 1 o’clock there is a moon phase display that just needs to be corrected by a day after 577.5 decades. Beneath the moon phase display at roughly 4:30 is a power reserve indicator. Ultimately, we have the highlight of the watch, the massive tourbillon featuring a constant-force mechanism that delivers power in even impulses into the escapement. In theory, this should enhance the chronometric performance of the movement.