The short answer
There is no factory building a 1:1 fake Atmos 566. The Atmos 566 is Jaeger-LeCoultre's torsion pendulum clock movement, and it runs on a sealed gas capsule that expands and contracts with room temperature. Copying that at scale costs more than the finished clock sells for. What does exist is messier: vintage Atmos clocks rebuilt from mismatched parts and listed as 566s, plus cheap Chinese torsion clocks that borrow the silhouette. So when you open a listing, you are not grading a clone. You are deciding whether the thing in the photos is a real Atmos, a marriage of parts, or a lookalike with a battery hiding in the base.
What the Atmos 566 really is
The 566 is the calibre JLC lists for the current Atmos Classique and Atmos Transparente. Earlier Atmos clocks ran 526, 528, 540 or 561 calibres, so the number is a claim about age as much as anything. It is also engraved on the movement back plate, right next to the serial, which is visible through the case on most references. That is your first fact to verify, not the dial font.
The mechanism is the interesting part. A sealed capsule holds gas that expands as the room warms and contracts as it cools. That expansion winds a mainspring a little at a time, and the mainspring drives a torsion pendulum that turns once a minute. No tick. No winding crown. No power cord. A genuine Atmos can keep running for years on ordinary temperature swings, which is why a quartz imitation falls apart under a loupe in about ten seconds.
Why nobody has cloned the 566
The replica watch world has factories that will spend real money on a case mold because a popular steel sports watch sells in volume. Table clocks are a different market. Shipping is bulky, buyers are collectors rather than impulse shoppers, and the gas capsule and torsion assembly are the expensive parts. There is no margin in faking one properly. What the market produces instead is the same thing it produces for vintage wristwatches: rebuilt pieces passed off as original.
Three things sold as a fake Atmos 566
- Rebuilt vintage clocks. A real 526 or 540 movement dropped into a later case, a repainted dial, swapped hands, and a listing that calls it a 566. The movement may be genuine and still wrong for the clock.
- Chinese torsion clocks. New manufacture, often with a visible coil spring or a decorative brass tube instead of a gas capsule, printed markings on the back plate, and thin glass that flexes when you press it.
- Quartz lookalikes. A battery hatch under the base, hands that step once a second, and a pendulum arm that is bolted on and does nothing.
How I check one before buying
- Find the serial and calibre engraving. It should be cut into the metal, not printed on a plate or a sticker.
- Locate the transport locking lever. Genuine Atmos clocks have one to hold the pendulum during shipping. A seller who has never heard of it is telling you something.
- Look at the capsule behind the dial. Real bellows are a sealed metal can with clean soldering, not a spring or a tube.
- Weigh the glass in your hand when you can. Mineral panes have a slight distortion at the edge. Acrylic feels like what it is.
- Ask for a photo of the movement running with the case open. A 566 pendulum rotates once a minute and makes no sound at all.
- Cross-check the serial against JLC service records or a past auction lot. Mismatched movement and case numbers are the most common flag.
Price reality
Modern Atmos Classique clocks sell near five figures at retail, and Transparente references sit higher. Vintage Atmos clocks trade from a few hundred dollars for rough examples up to several thousand for clean, complete pieces with the box. That spread is where the problem lives: a rebuilt clock bought for $400 and relisted at $2,500 as a 566. When a price lands far under the market for the reference, you are not getting a bargain on a real one.
Bottom line
Treat fake Atmos 566 as a warning label rather than a product category. There is no super clone of this movement, and any seller promising one is either confused or hoping you are. Buy the seller, insist on movement photos, verify the calibre and serial, and walk away from anything with a battery compartment. The same discipline that keeps replica watch buyers out of trouble applies here, only more so, because Atmos clocks are hard to service and easy to fake with a case and a dial.