The number 1678420 is not a valid Jaeger-LeCoultre reference. Jaeger-LeCoultre uses the letter Q followed by seven digits, or those digits split into groups such as 136.84.20, which means any listing labeled "Jaeger-LeCoultre 1678420" is replica, mislabeled, or a scrambled version of the genuine reference Q1368420, the Master Ultra Thin Moon in stainless steel. Treat the number as a seller code, never as a factory reference.
What Is Jaeger-LeCoultre Reference 1678420?
No Jaeger-LeCoultre catalog, price list, or auction archive lists a 1678420 reference. The sequence sits one digit away from Q1368420, the Master Ultra Thin Moon 39 mm in steel, a model replicas copy heavily because of its moon phase and sunburst dial.
Jaeger-LeCoultre 1678420 Fake Copy Watch: What the Reference Means
Replica sellers routinely scramble, pad, or drop digits so their listings do not collide with the genuine model in search results. When a title shows 1678420, the seller is describing a counterfeit or a typo, not a Jaeger-LeCoultre production code.
fake jaeger lecoultre 1678420 replica
How Does Jaeger-LeCoultre Format Reference Numbers?
Modern Jaeger-LeCoultre references begin with Q and contain seven digits, for example Q1368420 or Q4018420. Older and vintage pieces use a six-digit numeric system, such as 145.8.79 or 270.8.62.
- The Q prefix signals a current or recent production reference.
- The digits break down into model family, case size, and metal or strap code.
- The caseback engraving must match the reference printed on the warranty card exactly.
What Gives Away a Fake Jaeger-LeCoultre Replica?
Most JLC replicas fail on the moon phase, the dial text, and the caseback engraving.
- Moon phase disc: genuine discs use a deep blue background with a photo-etched gold moon; replicas use flat ink and a printed circle.
- Dial printing: the Jaeger-LeCoultre wordmark should be crisp with even serif weight, while replicas show fuzzy or uneven lettering.
- Movement: the Master Ultra Thin Moon uses Calibre 925/1, and a replica usually hides an unbranded decorated movement under the caseback.
- Caseback: engraving depth, font, and serial should be laser sharp; replicas often show shallow acid etching.
- Weight and feel: solid gold references are noticeably heavier than a replica steel or plated case.
How Do You Verify a Jaeger-LeCoultre Before Buying?
- Ask for the reference and serial number and compare both against a clear caseback photo.
- Request a movement photo and a timegrapher reading rather than a stock image.
- Order an Extract from the Archives from Jaeger-LeCoultre, which confirms reference, production date, and original retailer.
- Have a qualified watchmaker open the caseback before any money changes hands.
A legitimate seller will supply all four without hesitation. A listing that hides the serial number or refuses movement photos is a replica listing with a real reference painted on it.
Is Buying a Fake Jaeger-LeCoultre Legal in the United States?
No. Selling, importing, or trafficking counterfeit watches violates US trademark law, and US Customs and Border Protection seizes counterfeit shipments at the border.
Buyers also risk losing the purchase price with no recourse, since counterfeit sales carry no warranty and platforms can reverse charges once fraud is reported.
Does a 1678420 Listing Ever Describe a Real Watch?
Only as a typo. If the seller meant Q1368420, ask for a caseback photo with the reference visible and matching papers. If the metal does not read Q1368420, the watch is not the model being advertised.