From the manufacturer

Eco-Drive | Purposeful Power

The sustainable way to power your watch—no batteries required. Citizen’s proprietary Eco-Drive technology powers your watch using the most renewable energy: light.

Light to Energy

Uses a renewable natural resource by converting any natural or artificial light to energy, which is then stored in a permanently rechargeable lithium-ion cell.

Energy Storage

Keeps surplus energy in a rechargeable power cell. Designed to charge not just from the sun, but also from everyday light sources like indoor fluorescents and desk lamps.

Recharges Continuously

Runs for months—even in darkness—with no need for regular battery replacement, so your watch can run forever and you never have to worry about it stopping.