Mondaine - Digi-Solar

European Watch Clock and Jewellery Fair 1978 BF 328
After the 6-digit solar-cell watch, Mondaine introduces the 10-digit readout: hours, minutes, seconds, date and alphanumeric day of the week. Its calendar is programmed to the year 2100. The battery is constantly recharged by sunlight or artificial light. These models are also available with standard power source instead of solar cells. (MONDAINE - Digi-Solar)