<P> Since 2009, Citizen has developed Eco-Drive Concept Models as technology demonstration and marketing tools . These Eco-Drive Concept Models are generally shown at exhibitions and produced in limited editions . The Concept Model 2011 was the Eco-Drive SATELLITE WAVE that has a movement that can receive time synchronization signals from GPS satellites . This makes radio - controlled timing possible in remote areas that are not serviced by land based radio time signal stations . In 2012 Citizen announced the Eco-Drive RING Concept Model . This watch features a ring - shaped solar cell surrounding the watch case sidewall . </P> <P> According to Citizen, by 2011 80% of their wristwatches featured Eco-Drive, and the company saw Eco-Drive type watches as the focus of new generations of watches . </P> <P> In 2012 Citizen offered over 320 Eco-Drive watch models in various types, styles and price ranges . </P> <P> Most Eco-Drive type watches are equipped with a special titanium lithium ion secondary battery charged by an amorphous silicon photocell located behind the dial . Light passes through the crystal and dial before reaching the photocell . </P>

What does eco drive mean on citizen watches