If you are shopping for a fake Cartier Tank Must Medium, the pick is the high-tier quartz build that matches the mid-size steel case proportions, uses a sapphire crystal, sets a spinel cabochon in the crown, and prints the dial cleanly enough to hold up under a loupe. That recommendation rests on six checks: case size and thickness, dial printing and layout, crystal and crown, movement type, strap and buckle, and how the seller answers questions before you pay.

Why the Tank Must Is Hard to Replicate

The Tank Must is a plain-looking watch with nowhere to hide. The case is a flat rectangle with softened corners and a gentle curve into the lugs. The dial is silvered, with Roman numerals, a chemin de fer minute track, and blued steel hands. There is no busy bezel, no chronograph subdial, no textured finish to distract the eye from a mistake in proportion.

That is why tier matters more on this model than on a chunky dive watch. A low-grade Tank copy can look convincing in a phone photo taken at an angle and fall apart the moment someone sits across a table from you. The good news is that the same simplicity makes the checks easy to run once you know what to look for.

Check One: Case Size and Thickness

Cartier offers the Tank Must in more than one size, and resellers blur the names. Before you compare anything, pull the official dimensions from the brand's own product page for the size you want, then ask the seller for caliper photos of the actual watch, not a stock image. Thickness is the number most cheap builds get wrong, and it is the tell you notice when the watch sits on a wrist under a shirt cuff.

• Pros of a top-tier case: correct length-to-width ratio, sharp but not knife-edged corners, lug curve that follows the wrist, thickness within a fraction of the original.
• Cons of a budget case: slab-sided profile, soft or rounded corners from buffing, lugs that sit flat and leave a gap at the wrist, thickness that reads bulky on a small wrist.

Best for: anyone who wears the watch with a dress shirt or a suit. Case geometry is the single most visible difference from across a room.

Check Two: Dial Printing and Layout

The dial is where mid-tier replicas win or lose. Compare the Roman numerals against a reference photo at the same focal length. Look at the weight of the numeral strokes, the spacing between the minute track and the numerals, and whether the hands are the right shape and finish.

• Pros of a strong dial: crisp printed track with no bleed, numerals that keep their serifs, hands with a flat blue finish that shifts in light rather than a painted-looking blue.
• Cons of a weak dial: thick or blobby printing, a minute track that crowds the numerals, hands that are too short or too wide, a silver finish that reads gray or yellow next to the case.

Best for: buyers who plan to wear the watch close to other people, in a meeting or at a dinner table. Dial print is what gets inspected.

Check Three: Crystal, Crown, and Cabochon

The crown on a Tank Must is a small, fluted piece with a blue cabochon set into the end. Cheap builds use glass beads or painted epoxy that looks flat and plastic. The crystal should be sapphire on a good build, with a slight dome and no visible distortion at the edges.

• Pros: sapphire that resists scratches, a cabochon with depth and a rounded dome, correct crown fluting that you can feel with a fingernail, no glare-heavy coating that turns the dial milky.
• Cons: mineral glass that scratches in weeks, a cabochon that looks like a dot of nail polish, an oversized crown that breaks the case line.

Best for: daily wear. If the watch will see a desk, a keyboard, and door handles, the crystal and cabochon are what keep it looking intact after a year.

Check Four: Quartz or Automatic

The genuine Tank Must in steel runs on a quartz movement, which is good news for replica buyers: a quartz copy has fewer visible giveaways than an automatic copy of a watch that was never automatic in the first place. A sweeping seconds hand on a Tank Must is a mismatch.

• Pros of quartz: correct behavior for the model, thin case, low maintenance, no rotor noise, easy to service or swap.
• Cons of quartz: battery changes every couple of years, and a cheap module can tick with a visible stutter.
• Pros of automatic: none that apply to this reference, unless you specifically want a mechanical watch and accept the mismatch.

Best for: almost every buyer. Ask which movement is inside and whether the seconds hand sweeps or ticks. If a seller dodges the question, treat that as your answer.

Check Five: Strap, Buckle, and Caseback

Straps are the easiest place for a builder to cut cost, and the easiest place for you to upgrade later. The buckle and caseback engraving are harder to fix.

• Pros: a leather strap with a firm temper and stitched edges, a correctly proportioned pin buckle, caseback engraving with even depth and correct font.
• Cons: thin, shiny leather that creases within a month, an oversized buckle, shallow laser engraving with rounded letter edges.

Best for: buyers on a tight budget. Buy the better case and swap the strap yourself, since aftermarket straps are cheap and case work is not.

Check Six: Seller Proof and Packaging

Ask for timestamped photos of the exact watch, a short video showing the dial in motion, and the movement type in writing. A seller who sends factory photos of a different unit, or who cannot name the build they are offering, is a risk regardless of price.

• Pros: real photos on request, clear answers about movement and dimensions, packaging that matches the order, a stated return policy.
• Cons: stock images only, vague answers, pressure to pay through a channel with no recourse, a box that arrives damaged or not at all.

Best for: first-time buyers. The cost of a bad seller is the whole order, not a few dollars.

What the Law Says

A replica Cartier is a counterfeit product. Selling one infringes Cartier's trademarks, and customs authorities in the United States can seize counterfeit watches at import. Buying one for personal use carries lower risk than selling, but the risk is not zero, and reselling a replica as genuine is a serious offense in most jurisdictions. Treat this guide as product research, and decide for yourself what you are comfortable with.

Bottom Line

Buy the case and the dial first. Get caliper photos, confirm the crystal and cabochon, confirm quartz, and only then argue about the strap. A fake Cartier Tank Must Medium that gets the case proportions and dial print right will hold up in normal wear, and that is the whole point of picking the high tier over the cheap one.