Turning the watch over reveals an equally open back with the tourbillon, the two mainspring barrels, the wheel train and the winding and time-setting mechanisms all visible.?
Horizontally configured dual mainspring barrels drive two vertical gear trains, transferring power to the twin pods indicating hours/minutes and power reserve.
A curving conical pulley with a chain wrapped around it attached to the mainspring barrel, it changed the leverage as the spring unwound, equalizing the drive force.
