Short answer: IW329135 is an IWC Aquatimer Automatic reference. Fakes of this reference are less common than fakes of the Portugieser or Pilot's Watch lines. The strongest tell is the movement behind the display back. Genuine watches use an IWC in-house calibre. Replicas use a stock Asian automatic with a decorative plate.

What the reference is

IW329135 falls in the IW3291 block. IWC assigns that block to the Aquatimer Automatic, a 42 mm steel dive watch rated to 300 m. The model carries an inner rotating bezel and a screw-in crown. Case size, movement and water resistance change between editions, so confirm the exact variant on IWC's reference page before you compare details.

Five checks that catch most fakes

1. Dial text and markers

Genuine IWC dial printing has sharp edges and even spacing. Look at the gap between the city name and the depth rating, and at the shape of the date numerals. Replicas show thick text, uneven gaps and a date font with wrong numeral curves. Compare at the same angle and light.

2. Caseback engraving

Genuine engraving cuts clean and deep, with crisp edges on the reference number and the serial. Replica engraving looks shallow, often laser-etched. The serial on the caseback should match the number on the warranty card.

3. The movement

The Aquatimer Automatic shows its movement through a display back. A genuine calibre shows IWC finishing: striped bridges, a signed rotor, polished screws. Replica movements show a printed plate, rough edges and a rotor that sits above the caseback line.

4. Bezel and crown

Turn the inner bezel through a full rotation. Genuine units move with firm detents and no side play. The crown should thread with no grit and seat flush against the case. Replicas show slack bezel action and crowns that catch on the first thread.

5. Weight and strap

A genuine steel Aquatimer head weighs more than a replica of the same size. Strap hardware is the second giveaway. Genuine rubber straps carry crisp moulded text on the underside, and the buckle edges are chamfered. Replica straps show soft moulding and sharp buckle edges.

Paperwork, serials and price

Aquatimer Automatics trade on resale sites in the low thousands of US dollars, with the figure driven by age, box and papers. Replica sellers ask a few hundred. A watch priced far under market with no service history is either a fake or a build from mixed parts. Ask for the serial, then call an IWC service centre and confirm it.

If you already bought a fake

Stop the payment if it has not cleared. File a dispute with the card issuer or the marketplace. Keep the listing, the photos and the chat log. Counterfeit watches are subject to seizure at the US border, so do not plan to resell it.