Automatic (Or Self-Winding)
This complication replaces manual winding in wristwatches by converting the wearer’s everyday motions into stored energy, which powers the mechanical movement. A winding box may also be used to achieve the same results. For both methods, the motion spins a rotor connected to the movement, which generates energy by tightening the mainspring. It’s also worth noting that an automatic movement may also be wound using the crown.