Jaeger-LeCoultre ATMOS 528-8 Swiss clock, serial number 258428, dating from 1967; it features 15 jewels and has been recently serviced. Here we have one of the most extraordinary pieces in the world of horology, the magic of which lies in an almost philosophical principle: it requires neither manual winding nor a battery. It operates based on fluctuations in ambient temperature and atmospheric pressure. The mechanism is powered by a hermetically sealed capsule filled with a special gas. When the temperature changes by just 1°C, the gas expands or contracts, actuating a bellows that winds the mainspring driving the clock. This slight temperature variation allows the Atmos to store enough energy to run for two full days. It continuously rewinds itself to maximum capacity. Theoretically, as long as the clock remains in a room with temperature fluctuations, it will run indefinitely without any manual intervention. Please examine the photographs carefully; they are part of the description. The clock will be securely packed in two boxes for shipping.