An Atmos Clock is a highly innovative mechanical clock that requires no manual winding or batteries. Invented in 1928 by the Swiss engineer Jean-Léon Reutter and later perfected by Jaeger-LeCoultre, the clock is powered by minute changes in atmospheric temperature and air pressure. A sealed capsule containing gas expands and contracts with even the slightest fluctuation in temperature, providing enough energy to keep the clock running for long periods. Celebrated for its exceptional engineering, precision and elegant design, the Atmos Clock is regarded as one of the finest achievements in twentieth-century horology.