Short answer
A fake Cartier Tank Louis Cartier usually fails on the case, not the dial. The genuine watch is a thin rectangular 18k gold case with a sapphire cabochon crown, Roman numerals, a chemin de fer minute track, and blued steel sword hands. Most replicas copy the printed dial well and lose the proportions, the metal, or the crown. Judge a replica the way a watchmaker would: measure it, weigh it, and study the crown and caseback before you look at the front.
Know the reference before you judge the watch
The Tank Louis Cartier is a specific model line, not a generic rectangle. Case sizes, movement type, and dial layout changed across decades of production, so a replica can be wrong on one reference and pass on another. Pin down the exact reference number and case size you are comparing against first. A watch that looks off against the wrong reference tells you nothing.
Prerequisites
- A caliper or a ruler accurate to 0.5 mm, plus a scale that reads to 0.1 g
- A 10x loupe or a phone macro lens for close inspection
- The exact reference number and case size of the model you are using as a baseline
- Good daylight or a color-corrected lamp, since dial printing and blued hands read differently under warm indoor light
Step-by-step evaluation
- Measure the case across the bezel width, the lug-to-lug length, and the thickness. The large Tank Louis Cartier runs roughly 33.7 mm by 25.5 mm and sits near 6.6 mm thick. Replicas commonly run 1 to 2 mm wide or thick, which throws off the slim profile that defines the model.
- Check the case profile from the side. The genuine case has a soft, even curve with polished flanks and sharp, controlled edges where the bezel meets the case band. Replicas often show a flat, slab-sided band or rounded edges from stamping.
- Inspect the crown under magnification. It should be fluted with a faceted sapphire cabochon seated flush in the center. Fakes use plastic or glass cabochons that sit proud, wobble, or show a milky tone instead of a deep blue.
- Read the dial printing with the loupe. Roman numerals should be crisp and evenly spaced, the chemin de fer track should have consistent squares, and the brand signature should sit cleanly with no double printing or bleeding. Look at the secret signature worked into one of the numerals.
- Examine the hands. Genuine blued steel sword hands have a deep, uniform blue from heat treatment. Replicas are painted, so the color looks flat, and the edges of the hand often look thick or uneven.
- Turn the watch over and read the caseback. Reference number, serial number, metal content, and any assay hallmark should be engraved deeply and align with the reference you are checking. Laser-etched or shallow markings that catch light in the wrong way are a common sign of a copy.
- Weigh the watch. A solid 18k gold case carries real mass. A replica with gold plating over steel or brass feels light in the hand for its size, and the difference grows once you handle both side by side.
- Confirm the movement type for that reference. Note whether the model should be quartz or hand-wound, then match the caseback and any movement marking to it. A quartz tick in a reference that should be mechanical, or the reverse, is an immediate mismatch.
- Compare the strap hardware last. Pin buckles and deployants should carry the same finish and engraving quality as the case, with no soft casting lines or plating wear at the edges.
Where replicas usually fall short
Thickness and weight are the two hardest details to fake at a low price point, because correcting them means machining a different case rather than reprinting a dial. Crown construction and sapphire cabochons come next. Dial printing is where replicas perform best, which is why so many buyers judge a watch by the front and get it wrong. Caseback engraving depth and movement correctness round out the list.
Legal and practical notes
Counterfeit watches carrying a protected trademark are illegal to import or sell in the United States. U.S. Customs and Border Protection seizes counterfeit goods, and selling them exposes a seller to trademark enforcement. Buying and wearing a replica is a different question from trafficking in one, but the practical risks, including resale difficulty, service refusal, and no warranty support, apply either way. If authenticity matters to you, buy from an authorized dealer or a seller who provides documentation for the specific reference.