The power reserve is a functional feature that is included in a watch's dial or movement and displays the remaining energy stored in the mainspring of a mechanical watch. This enables watch wearers to detect how much power is left before the watch requires winding, or in an automatic watch, requires being worn to maintain its power. Power reserve indicator

This complication is typically indicated through a small gauge or hand on the dial and provides essential information for the watch to work properly and accurately. This complication not only enhances the practicality of the watch but also highlights the intricacy and creative personality of the watch's mechanical design, which an enthusiast cherishes for both function and craftsmanship.