The short answer
A fake Jaeger-LeCoultre ref. 3518420 fails at least one of four checks: dial print, caseback engraving, movement finish, and serial continuity across the case, the movement, and the papers. A genuine seller supplies photos for all four. A replica seller stalls on at least one.
Why this reference gets copied
Ref. 3518420 sits in the part of the JLC catalog that buyers chase most: a restrained dial, an in-house automatic caliber, and a case size that suits a range of wrists. That mix is what makes it worth copying. A simple dial layout is cheap to print, a solid caseback is cheap to laser, and the finished product photographs well enough to pass a phone screen. It stops passing the moment you put a loupe on it.
What to have ready
- A 10x loupe, or a macro lens on a phone
- Indirect daylight, not a jewelry case lamp
- A full photo set from the seller, movement included
- The reference and caliber listings published by Jaeger-LeCoultre
Inspection steps
- Ask for a straight-on dial photo shot in daylight, with no filter.
- Compare the wordmark against a known-genuine photo. Genuine JLC lettering is thin, even, and sits level with the dial. Replica print runs thick and drifts at the ends.
- Check the hands and markers under the loupe. Genuine hands carry polished bevels and sharp tips. Replica hands look flat and show burrs at the tip.
- Photograph the caseback at a low angle. Genuine engraving cuts into the metal with a defined edge. Laser engraving on a fake sits on the surface and washes out in raking light.
- Write down the reference number and the serial number, then compare both against the certificate.
- Book the watch with an independent watchmaker and have the caseback opened in front of you.
- Study the rotor and bridges. Genuine JLC applies Cotes de Geneve stripes, circular graining, and blued screws to a high standard. Clones use decoration that looks printed under magnification.
- Turn the crown through a full wind and set the time. Genuine action is smooth and firm. A gritty or loose crown points to a swapped stem or a non-JLC movement.
- Weigh the watch on a kitchen scale and compare the figure against the published spec for the reference.
- Match the box, booklet, and certificate against the watch. Mismatched packaging is the last check and often the fastest one.
Movement checks that settle it
The caliber is the hardest part to fake and the easiest part to verify. Jaeger-LeCoultre builds its own movements, and the finish standard holds across the range. Look for even Geneva stripes, circular graining on the mainplate, mirror-polished screw heads, and rotor engraving that follows the curvature of the rotor without gaps. Copies of ref. 3518420 often use an ETA or Miyota base with an engraved rotor plate bolted on. The tell is depth. An engraved rotor has material removed. A plated rotor has none.
Serial and paperwork checks
Genuine JLC serial numbers run as a continuous string and repeat across the caseback, the movement, and the certificate. If any of the three differs, stop. Service papers should name the watchmaker and carry a date that fits the watch history. A seller who offers a box with no certificate, or a certificate with a number that does not match the case, has given you the answer already.
Listing red flags
- Movement photos are missing, blurred, or lifted from another listing.
- The listing uses clone grading terms such as 1:1, AAA, or super clone.
- The price sits far under market for the reference with no stated reason.
- The seller refuses a third-party inspection or a face-to-face handover.
- The photos show a different reference number than the text.
If the watch fails a check
Walk away and keep the photos. If you already paid, report the transaction to the platform and to your payment provider, and file a report with the brand anti-counterfeiting team. Counterfeit watch sales violate trademark law in the United States, and a documented report supports a chargeback.