Quick answer
The "2370" code is a case reference stamped on the back of certain Cartier Tank models, and it gets used as loose shorthand for the whole family. A fake Cartier Tank 2370 can mean anything from a $40 quartz knockoff to a $700 1:1 build with a screw-back case. You cannot confirm authenticity from one photo. You confirm it by reading the case-back engraving, the crown cabochon, the dial printing, the movement, and the paperwork together as one set.
Before you start
- A 10x jeweler's loupe
- A bright light you can angle across the metal
- A digital scale and a caliper, if you have them
- Full-resolution seller photos, not compressed thumbnails
Inspection steps
- Turn the watch over and read the case-back reference and serial. Genuine Cartier stamps are shallow, crisp, and even in depth, so compare the digit shapes against a known reference photo.
- Check the case-back screws on steel Tank cases. Genuine screws sit flush with matched slot widths; replica screws sit proud, strip easily, or show slots cut at different angles.
- Examine the crown cabochon under light. A genuine cabochon is a domed synthetic spinel with a polished surface and a clean seat in the crown.
- Compare dial printing at magnification. Genuine "CARTIER" lettering has even stroke weight, sharp serifs, and a minute track that does not bleed into the numerals.
- Look for the secret signature woven into the Roman numerals, usually inside the VII or the X, and check whether it is engraved or simply printed on top of the paint.
- Study the hands. Genuine hands reach the minute track exactly, with a consistent blue finish or polished steel and no burrs at the tips.
- Weigh the watch and measure the case across the lugs. A hollow case and a lightweight bracelet usually point to a low-grade replica.
- Ask for a movement photo. Genuine quartz and automatic Tank calibres carry signed rotors and clean finishing; replicas often show a generic movement with the wrong engraving.
- Inspect the bracelet and clasp. Genuine links are solid on newer references, the clasp stamping is deep and centered, and the folding action is smooth without side play.
- Match the warranty card, box, and serial to the case. Modern Cartier cards carry the same serial as the watch, so a mismatch is a hard stop.
- Have a watchmaker or a Cartier boutique open and authenticate the piece before any money changes hands.
Replica grades you will run into
- Budget tier, roughly $30 to $80: quartz movement, painted dial, folded bracelet, flat plastic cabochon.
- Mid tier, roughly $150 to $350: mineral or basic sapphire crystal, closer case proportions, generic Japanese quartz.
- 1:1 tier, roughly $400 to $800: correct case dimensions, screw-back case, engraved rotor, domed spinel cabochon, sapphire crystal with coating.
What the 2370 stamp actually means
Cartier uses case reference numbers to identify a case shape and size family, not an individual watch. A single Tank reference can cover several dial variants, metals, and bracelet options made across many years. Individual watches are tracked by the serial, which is why sellers who lean hard on the "2370" tag without showing the serial and movement are usually hiding something.
Red flags in a listing
- Stock catalog photos only, with no real shots of the actual watch
- No movement photo or refusal to open the case back
- A price far under market for the reference
- Pressure to pay outside a protected payment method
Is a fake Tank 2370 water resistant?
Most replicas are not rated, even when the listing claims 30 m. Gaskets are usually absent or undersized, so keep any replica away from water.
Can a jeweler spot one instantly?
A trained watchmaker usually can, once the case back is open. External checks alone catch the low and mid tiers; the better 1:1 builds need the movement and serial check.