Eco-Drive
Eco-Drive watches use a battery recharged by a solar panel hidden under the watch face. In the rare and discontinued Eco-Drive Duo series, the solar power was supplemented by an automatic quartz power source. There was also an Eco-Drive Thermo model that exploited temperature differentials between the wearer's skin temperature and ambient temperature to recharge the battery. However, the only Eco-Drive system currently described on the Citizen Watch official web site is the one depending solely on light to recharge. Features similar to the Eco-Drive have been developed by other manufacturers like Casio or Junghans. All Citizen Eco-Drive models are made in Japan but may also be assembled in China.
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