Eco-drive is the term given to our market-leading, award winning, light powered technology. Simply put, any watch displaying the name 'Eco-drive' on the dial will never need a periodic battery replacement. Light enters the watch through the dial and in turn charges a rechargeable capacitor. The power stored in the capacitor then runs the watch. Find out more about Eco- Drive by following this link: "Eco-Drive Explanations Video"