The Slim Solar collection beats in rhythm with nature. Its energy source is environmentally friendly and infinitely available: light. Not just sunlight, but all types of light are converted into electrical energy by the solar cell beneath the dial and stored in a rechargeable secondary battery. No battery change, as with quartz watches, is necessary. The watch has a power reserve, allowing it to run for 6 to 12 months once fully charged, even if stored in complete darkness during that time. It features scratch-resistant sapphire glass and an ultra-light case and bracelet made of titanium.