Some self-winding watches feature a power reserve display as a so called small complication. The power reserve designs the time an automatic, self-winding or mechanical watch has left to run before it has to be winded up – either mechanically through winding it up or through movements. The extension spring of the movement determines this period of time. The power reserve display occurs through a scale on the dial of the watch. This scale had been identified in the past through “high and down”, nowadays scale graduations will be used as well as absolute hours. The advantage of the display of such power reserves is to have an information about how tight the extension spring is, that means to know if it needs to be winded up or not before the reserve is completely utilised. It allows to avoid that the watch stops itself by mistake and subsequently to have to adjust the time. The power reserve is to be found on the upper third of the dial of the watch “Réserve de marche” from Mathis Montabon through a scale with a watch hand.