Jaeger LeCoultre Atmos perpetual motion clock, 526-5 ("baby") model, serial number 3157907, made in 1970 (date on bellows 1-10-70). The good running condition, keeps accurate time (+/-5 min. per week), the movement is in good condition, recently cleaned, bellows inspected, works well. The case has some minors signs of usage (see pictures and video for more details https://youtu.be/0tG0iDAkrfM ) Secure shipping using double-boxed packing, Jaeger-LeCoultre's famous 'Atmos' clock was first developed in 1928. "JLC ATMOS clock is one of the world’s most innovative clocks, the Jaeger-LeCoultre Atmos is a visionary technical masterpiece. Powered by atmospheric pressure and temperature changes, it’s essentially a perpetual motion device, allowing ittorun for years without human intervention. The Atmos is such a ground-breaking creation that it’s chosen as a traditional gift to heads of state and dignitaries". A change in temperature of one degree can provide enough power to run the clock forfewdays, and the mainspring has enough power in reserve to run the clock for a year. Energy is conserved by the very slow-moving twisting pendulum which 'beats' only twice per minute. The movement is very silent. Warning!!! These clocks can have troubles to wind in premises with high quality climate control systems (where air temperature is very stable).