Short answer
A fake IW329064 copies the IWC Aquatimer Automatic 42. The real reference is a steel dive watch with a 42 mm case, an inner rotating bezel, and an IWC automatic movement. IWC does not publish a full public spec sheet for every dial variant, so treat a seller spec sheet as a claim to check, not as proof. Counterfeits in this line turn up on classifieds, social media, and some auction lots. The parts that fail first are the inner bezel, the crown threads, the caseback engraving, the movement, and the paperwork.
What the reference number means
IWC uses the IW3290xx block for Aquatimer Automatic 42 models. The last digits mark the dial and finish. Confirm four numbers on the watch you hold: case diameter, case thickness, water resistance rating, and calibre. Genuine Aquatimer Automatic 42 watches run IWC calibre 30120, an automatic movement based on the Sellita SW300. Ask the seller for a photo of the movement and the caseback before you talk price.
Case and bezel checks
- Measure the case at 3 and 9 o'clock with a caliper. Ask for a photo of the caliper jaw on the case. A case that reads far off 42.0 mm is not an IWC case.
- Turn the outer bezel. On the SafeDive system the inner ring moves with the outer ring. If the inner ring stays still, or the outer ring spins with no detents, walk away.
- Check the crown. Genuine threads take a full turn with light resistance. Fake crowns bind, cross-thread, or sit proud of the case.
- Look at the crystal edge. Sapphire shows no mold line. Mineral glass on a fake shows a haze at the edge under a light.
Dial, hands, and lume
Use a 10x loupe. Genuine dial print has sharp edges and even spacing between the index marks. Fake dials show fuzzy print, uneven lume plots, and a date wheel that sits off center. Charge the lume with a phone light for 30 seconds, then compare glow after two minutes and after ten minutes. IWC lume fades in a steady curve. Cheap lume drops fast or glows blue-white instead of green-blue.
Movement checks
- Calibre 30120 beats at 28,800 vibrations per hour. A quartz fake ticks once per second. An 8-beat fake shows a stutter.
- Ask for a timegrapher photo. Rate, amplitude, and beat error are printed on the screen. A rate far outside plus or minus 10 seconds per day needs an explanation.
- Rotor noise gives a fake away on video. Listen for a scrape, not a soft whir.
Caseback and paperwork
The caseback carries the reference number, the case number, and the IWC mark. Fake engraving is shallow and laser cut with wrong font weight. Genuine engraving has depth and sharp edges. IWC can confirm a reference and case number, plus service history, at a boutique or service center. Call before you pay. A box and warranty card without a matching case number prove nothing.
Price signals
Secondary market prices for Aquatimer Automatic 42 watches sit in the low thousands of US dollars. Check live listings for the reference you want. A price far below that range is the strongest single signal of a fake. So is a seller who refuses a caliper photo, a movement photo, or a video call.
Steps before you pay
- Get the reference number and case number from a caseback photo.
- Ask IWC or an authorized dealer to confirm both numbers.
- Request caliper measurements and a movement photo.
- Compare dial print, bezel action, and crown threads on video or in person.
- Check the asking price against current listings.
- Keep the listing, the messages, and the payment record.
If the watch is fake
Stop the payment. Keep the listing and messages. Report the seller to the platform. US Customs and Border Protection seizes counterfeit watches, and the Federation of the Swiss Watch Industry publishes seizure data. A counterfeit watch has no manufacturer warranty and no service support. Case numbers on fakes often repeat across many units, so a search of the number can surface other buyers with the same watch.