Hello Patrick,
Thank you for your prompt response and thank you again for sending your Atmos clock to Mearto.com for an appraisal. I shall try to help you with that today.
TITLE:
Rectangular, polished and brushed chromed stainless steel and glass, 'Atmos' clock, perpetual and self-wound by temperature and barometric pressure changes, Atmos V model, S/N 411727, Caliber 526-5 movement, made by Jaeger LeCoultre, Switzerland, circa 1974.
DESCRIPTION: Case: 166 x 224 x 120 mm in polished and brushed, chromed steel mantel timepiece with chamfered steel corner posts and 5 sided glass including the pediment at the top. The front door has a small pull in the lower left corner. Leveling screws are in the base plate of the lower case. The base has straight bracket feet and is otherwise a cube shaped clock case. . .
Dial: A two-tone grey metal chapter ring has applied steel upright Arabic hours at the quarter and dart shaped indices at the balance of the hours, is signed Swiss Made at the base and Jaeger LeCoultre across the glass over the dial. Silvered Dauphin hands.
Movement: JLC Calibre 526-5, a gilt brass, 15 jewel, shaped movement with a frame diameter of 45mm. Changes produced by temperatures and air pressure have tiny effects on a large vacuum chamber (marked Swiss) which winds the going barrel which produces the miniscule force to the torsion pendulum spring and round bob (with vertically fluted segments) which moves the lever escapement driving the hands on the dial.
There is a locking lever above the pendulum disc and a regulator at the top marked with the serial number 411727 and engraved 'Jaeger LeCoultre Atmos'.
Condition: Outer case of chromed steel has a moderate amount of scratches. The vacuum chamber is in good condition and the movement is assumed to be fully functional. Dial is in good-very good condition with a couple of scuffs and scrapes. Case and movement signed.
NOTES (CALIBER 526-5):
The Atmos V consists of the caliber 526 and the Atmos VI, VII, and VIII consists of the caliber 528 and the 528/1 represents the Atmos VIII. Serial numbers start at 70,000 and went right up to 599,999. The important point here is that this is the last of the “genuine” Reutter designed Atmos examples made and production stopped late in 1983.
526-5 & 528-6 & 529 & 532 have serial numbers from 70,000 - 106,999
526-5 & 528-6 & 528-8 have serial numbers from 107,000 - 599,999.
COMPARABLES:
https://www.barnebys.com/realized-prices/lot/jaeger-le-coultre-atmos-clock-aGJTA4Plx6B 9sold for $2000 in 2019)
https://www.liveauctioneers.com/item/80456927_lecoultre-and-cie-atmos-clock (ESTIMATED @ $300-$500 IT SOLD IN 2020 FOR $290, in brass)
https://www.liveauctioneers.com/item/75226772_circa-1950s-60s-jaeger-le-coultre-atmos-clock (SOLD FOR $240 IN 2019, in brass)
https://www.liveauctioneers.com/item/77396811_jaeger-lecoultre-atmos-clock (SOLD FOR $250 IN 2019, in brass)
https://www.barnebys.com/realized-prices/lot/jaeger-le-coultre-atmos-clock-H438g3hw_bb (sold on 2019 for $1800)
https://www.barnebys.com/realized-prices/lot/jaeger-lecoultre-atmos-no-410977-produced-in-the-1960s-fine-rectangular-steel-and-glass-atmos-clock-wound-by-barometric-changes-6FPKwhsRA (way back in 2004 your model was withdrawn because it had reached $1500 –I just show this because no one realized that prices would continue their decline for almost all clocks over the ensuing decade and a half.)
Pricing:
I do like the polished and brushed chromed steel appearance of your clock, and it is more unusual than the gilt brass models. I think in today’s auction market your clock would have a fair market value in the $1300-$1700 range. The original box it came in would increase the value, but it is not present. This is a handsome example of a type of case made in the mid- 1970s in far less numbers than the gilt brass cases. And since it is seen less often it brings a higher value in today's marketplace.
Thank you again for your prompt response to my request.
Enjoy this fine clock.
My best,
David

Hello Patrick,
Thank you for sending in this Atmos clock to mearto.com for an appraisal. In order for me to be as specific and complete as possible, could you please tell me the serial number of this clock? It is engraved into the escapement at the top. That is most important, but while you are doing that perhaps you can simply tell me all that is written on the movement plates. The photos are not clear enough for me to read them all.
Appreciatively,
David