A fake Cartier Tank Must in yellow is one of two things. Either it is a copy of the modern steel Tank Must with a yellow gold-tone plating job, or it is a counterfeit of the older Must de Cartier, the gold-plated line Cartier launched in 1977. The modern Tank Must has never been made in solid yellow gold, so a seller claiming otherwise is describing plating, a custom finish, or a straight-up copy. Four things separate the real thing from the rest: case size, dial printing, caseback markings, and the movement.
Why yellow is the first thing to question
Cartier relaunched the Tank Must in 2021 as a steel watch with a quartz movement, a Solarbeat version, and a run of lacquered dials in red, blue and green. No yellow gold case, no two-tone option. If the watch in front of you has a yellow case and the seller calls it a Tank Must, you are looking at gold plating over steel or brass, a vermeil vintage Must de Cartier, or a Tank Louis Cartier in 18k gold that is being mislabeled. Those are three different watches with three different price levels, and the label matters.
Sizes and case details worth memorizing
The proportions are the easiest thing to check with calipers or a ruler.
- Large Tank Must: 33.7 mm wide by 25.5 mm tall, about 6.6 mm thick.
- Small Tank Must: 29.5 mm by 22 mm.
- Caseback: four screws, not a snap-on lid.
- Crown: blue spinel cabochon, faceted, sitting flush in the crown.
- Water resistance: 30 meters on the current model.
Copies often run a millimeter or two fat, and the lugs get chunky. The brancards, the vertical bars on either side of the case, should be flat and crisp rather than rounded off.
Dial and crown checks
The dial is where most fakes fall apart. Cartier prints the Roman numerals sharp and even, with consistent spacing between the minute track and the outer edge. Look at the weight of the "Cartier" script and the placement of "Swiss Made" at 6 o'clock. Many Tanks carry a hidden Cartier signature worked into one of the Roman numerals; on copies it is missing, drawn into the wrong numeral, or stamped so heavily you can spot it across a room. The cabochon should be a deep, slightly translucent blue with facets you can feel under a fingernail. Plastic or glass beads read too bright and flat.
Caseback, movement and the price floor
Flip it over. Modern Tank Must casebacks carry a reference number, a serial, "Swiss Made," and Cartier engraving that is cut cleanly rather than lasered and fuzzy. Vermeil Must de Cartier pieces from the late 1970s and 1980s should show sterling silver marks alongside the gold plating stamp. Vermeil means solid silver underneath, never brass. Inside, the current Tank Must runs a quartz caliber rated for roughly eight years of battery life, a stretch that copy movements rarely match in daily use.
Price is the last filter. A new steel Tank Must starts around $3,000 at retail, and vintage vermeil Must de Cartier watches trade from a few hundred dollars up to roughly a thousand depending on condition and dial. A "yellow gold" Tank Must offered for a couple hundred dollars is not a bargain. It is a copy, and it will look like one on the wrist.
Before you hand over money
- Measure the case and compare it to the reference.
- Check the crown cabochon under a light and feel the facets.
- Read the caseback engraving for depth and clean edges.
- Confirm the metal: steel, sterling vermeil, or 18k gold. Never assume.
- Ask which movement is inside and expect a straight answer.