A watch winder is a device designed to keep your automatic watch running when it's not being worn by simulating wrist movement. Automatic watches rely on motion to wind their mainsprings and maintain accurate time. If left stationary for too long, they can stop, and the internal lubricants may begin to coagulate, which can cause the gears to seize. By using a watch winder, you ensure your watch continues to function properly, keeping it accurately wound and lubricated. This helps maintain the watch's performance and extends its lifespan, ensuring it's always ready to wear.