 Patented in 1928, the first version – known today as the Atmos 1 – was marketed by La Compagnie Générale de Radiologie (CGR) in 1930.It derives energy from small temperature and atmospheric pressure changes in the environment, and can run for years without human intervention.Wound by a capsule filled with a mixture of temperature-sensitive gases, a 1 °C fluctuation is enough to store sufficient energy to supply the clock with two days' autonomy.