Top pick: the replica worth your money is the one that gets the case profile and the movement right, not the one with the longest photo gallery. Judge a fake IWC IW329120 against five things: case geometry and finish, dial and hand detail, movement type and caseback, crystal and lume, and clasp plus paperwork. Everything else is sales talk. The sections below turn each of those into a pass or fail test you can run from photos, a caliper and a five minute hands-on inspection.

First, pin down the reference

The IW329120 sits inside IWC's 3291 reference series, and the trailing digits on these references change dial colour, case metal and strap configuration. Before you compare a replica to anything, pull the exact specification for the IW329120 from IWC's own catalogue: case diameter, thickness, lug width, crystal type, movement family and whether the caseback is solid or exhibition. A fake can only be called accurate against a fixed spec. Sellers who describe a watch as "IW329120 style" without naming the movement or the caseback type are telling you they do not want the comparison made.

Criterion 1: Case geometry and finish

Case dimensions are the hardest thing for a low-tier build to hide and the easiest thing for you to measure. Ask the seller for caliper readings across the bezel, lug to lug, and case thickness, then compare to the factory numbers. A case that is a millimetre thick or half a millimetre wide wears wrong on the wrist no matter how good the dial looks. Finishing is the second tell: genuine cases mix brushed flanks with polished chamfers, and the transition should be a crisp line, not a gradient.

• Pros: dimensions within a few tenths of a millimetre, sharp chamfer edges, brushing that runs in one direction, lug holes aligned and drilled at the same height.
• Cons: a bloated case profile, soft or rounded chamfers, polishing that bleeds onto brushed surfaces, lugs that sit at slightly different heights.

Use case: if you already own the genuine or you wear the watch daily, case accuracy matters more than anything else on this list, because it is the part you feel and everyone else sees in silhouette.

Criterion 2: Dial, hands and printing

Request macro photos with no flash and no heavy colour filter. Check that the markers at twelve line up with each other and with the centre line of the dial, that applied indices sit flush, and that the text weight matches the original rather than looking bolder or thinner. Look at the hand length: hour and minute hands should reach the correct track, not stop short of it. Lume fill should sit level inside the markers, with no overflow onto the dial surface.

• Pros: sharp printing with clean edges, consistent lume fill, hands finished on the underside as well as the top, date window cut square with the correct font.
• Cons: fuzzy text, misaligned markers, lume that spills over, date wheels that sit deep in the window or show a different numeral style.

Use case: this is the criterion for anyone who wears the watch to an office or a dinner. The dial is what people see at arm's length, and printing errors are visible without a loupe.

Criterion 3: Movement and caseback

Ask directly which movement is inside and whether it is automatic or quartz. An automatic should hack, wind with a smooth rotor, and hold a stated power reserve you can actually test overnight. On the caseback, compare engraving depth, font and layout against the reference photos. If the genuine has an exhibition back, the movement finish is on display and the rotor engraving becomes a graded detail; if the genuine has a solid back, a cheap movement is easier to conceal, so the seller's answers matter more.

• Pros: a named automatic movement, quiet rotor, accurate beat rate, caseback engraving that matches the reference in depth and spacing.
• Cons: vague answers about the movement, a rotor that rattles, engraving that looks etched rather than stamped, a caseback that does not seat flush.

Use case: for anyone who opens casebacks, resells later, or cares about serviceability, movement transparency is the deciding factor. Walk away from sellers who will not name a calibre.

Criterion 4: Crystal, lume and water resistance

Anti-reflective coating is a quick filter. Check how the crystal behaves under a lamp: a coated crystal nearly disappears at an angle, while an uncoated one throws a strong reflection. Lume should charge under a phone torch and still be readable after an hour in the dark. Treat any water resistance claim on a replica as unproven unless the watch has been pressure tested, and remember that the ISO 22810 standard defines how water resistance is tested and marked for watches generally.

• Pros: clear crystal with minimal reflection at an angle, lume that glows evenly across all markers, gaskets that look seated and clean.
• Cons: heavy glare, lume that fades in minutes or glows unevenly, a crown that feels loose when screwed down.

Use case: if you swim or shower in your watches, do not rely on a replica's rating. Wear it for dry use and keep a pressure-tested watch for water.

Criterion 5: Bracelet, strap and clasp

End link fit separates a careful build from a careless one. With the watch on a table, press lightly on the bracelet near the lugs: a good fit moves as one unit, a poor one clicks and gaps. Check whether links are held by screws or push pins, whether the clasp engraving is crisp, and whether the micro-adjustment actually works.

• Pros: flush end links with no daylight gaps, screwed links, a clasp that closes with a firm click and lines up square.
• Cons: rattling end links, push pins on a reference that should use screws, a clasp that sits off-centre or releases under light pressure.

Use case: for a daily wearer the bracelet takes more abuse than the case, so prioritise fit and hardware over cosmetic detail.

Criterion 6: Paperwork, serial and seller conduct

This is where most bad purchases happen. A seller who describes a replica as genuine is committing trademark fraud in the US, and both the FTC and US Customs and Border Protection treat counterfeit watch sales and imports as enforcement targets. Ask for photos of the actual watch with a timestamp, a short video showing the seconds hand sweeping and the crown operating, and a written return policy. Serial numbers that repeat across listings, stock photos presented as the item for sale, and pressure to pay outside a tracked method are all reasons to stop.

• Pros: clear disclosure that the watch is a replica, unique photos, a video on request, a stated return window, consistent answers across messages.
• Cons: claims of authenticity, reused serials, refusal to send new photos, no returns, payment methods with no recourse.

Use case: first-time buyers should weight this criterion above every other one. A well-built watch from a straight seller beats a perfect-looking watch from a seller who hides what they are shipping.

A five-minute verification checklist

1. Confirm the exact IW329120 specification from the manufacturer before comparing anything.
2. Get caliper readings for diameter, thickness and lug to lug.
3. Request macro photos of the dial under neutral light, straight on.
4. Ask for the movement name and confirm it hacks and winds smoothly.
5. Inspect caseback engraving depth and layout against reference photos.
6. Test the crystal under a lamp for reflection and the lume after a torch charge.
7. Check end link fit, link hardware and clasp alignment.
8. Read the seller's disclosure, return policy and payment terms in writing.

Which buyer are you?

If you want one watch to wear hard, spend your budget on case accuracy and bracelet fit, and accept a simpler movement. If you collect and compare side by side with the genuine, movement transparency and dial printing are the two criteria that decide whether the watch survives scrutiny. If you are buying your first replica, choose the seller first and the watch second: honest disclosure, real photos and a return window are worth more than any single cosmetic upgrade.