Delivered by two mainspring barrels, the energy level of the movement can be read by means of a digital display that shows the power reserve as the number of days of autonomy remaining. These indications are driven by a “crémaillère” rack system rarely seen in mechanical watches, consisting of a linear gear engaging a circular gear, moving in a straight line. A closer look at this system reveals a mechanism that is more subtle than it appears, composed of two superimposed disks rotating in opposite directions and connected by a spiral spring that coils in their centre like the barrel spring. This results in a very surprising differential display that is nevertheless intuitive to read.