The Citizen Quartz Crystron Solar Cell, launched in 1976, marked a significant milestone in watchmaking. It was the world's first analog quartz watch to incorporate solar cells, enabling the watch to operate for up to two and a half months when fully charged. This innovative technology eliminated the need for frequent battery replacements, making it a game-changer in the industry. The Citizen Quartz Crystron Solar Cell set the stage for the widespread adoption of solar-powered watches and positioned Citizen as a leading watchmaker.