Known as the perpetual motion clock the Atmos clock works on variations in atmospheric temperature and never requires winding.

Here we have a Jaeger LeCoultre Caliber 519 mantel clock with serial number 48004 which dates it to the early 1950's. 

 As can be seen from the photos this clock is in very good condition for its age.  There is some wear to the gilt on the case and particularly on the top of the case and the part of the base that surrounds the case.  The Atmos is keeping time to within +/- a couple of seconds per day which is pretty good for a 70 year old clock

The bellows of this clock are operating in accordance with the manufacturer's specification.  Why is this important?  The motor of the Atmos clock is powered by a gas-filled bellows that often fail over the years so the clock must be taken apart and manually wound in order to operate correctly.  With the bellows operating correctly there will be need to wind the Atmos clock.

The dimensions of this clock are 23.5cm high x 21cm wide x 17cm deep.