Casio edifice eqs-900db-1avudf (ex434) chronograph men's watch these models are the latest solar-powered chronographs from the high performance edifice lineup. The sporty designs of these motorsports concept timepieces are created using carbon fiber, an essential material for racing car applications, for their faces.a solar-cell is used to generate electrical power from light, which is used to charge a battery. This eliminates any need to worry about the battery suddenly going dead, as long as light is available. A full charge provides enough power for about five months of operation, even if there is no exposure to light. Though a solar powered watch normally requires a transparent face to allow light to reach the solar cell, the face of the eqs-900 is made of non-transparent carbon fiber.