Short answer

IW329140 is an IWC reference number. Numbers in the 3291 block belong to the Aquatimer Automatic line: 42 mm steel case, inner rotating bezel, automatic movement. A replica IW329140 is a watch made outside IWC that copies that design. It copies the look. It does not copy the movement, the case material, or the water resistance test.

The exact reference IW329140 does not appear on every public IWC catalog page. Confirm the number, dial color, and bracelet against an official listing before you compare photos.

What the reference number covers

IWC reference numbers combine family, case, dial, and bracelet. The final digits change when the strap or dial changes. Two watches with the same case can carry different numbers.

  • Family: Aquatimer, dive line.
  • Case: 42 mm, stainless steel, sapphire crystal.
  • Bezel: inner rotating ring, SafeDive system, driven by the crown at 4 o'clock.
  • Movement: IWC caliber 30120, automatic, hours, minutes, seconds, date.
  • Water resistance: 300 m on the steel Aquatimer Automatic 42 mm.

Where replicas differ

  • Movement: third-party or cloned calibers. Finishing, rate, and spare parts differ from IWC service.
  • Case finish: brushing and polishing lines sit shallow. Lug edges feel sharp.
  • Crystal and bezel: anti-reflective coating is thin. The inner ring can drift or skip a click.
  • Water resistance: no test to ISO 22810. Do not swim with a replica.
  • Dial print: weight and spacing of the Automatic and Swiss Made text vary.

Checks before you buy

  1. Ask for the movement name and a photo of the case back.
  2. Measure the case. A 42 mm claim that arrives at 41 mm or 43 mm is a different case.
  3. Ask for the bracelet code stamped on the end link.
  4. Ask for a pressure test result if the seller claims water resistance.
  5. Compare the date window position and the seconds hand length to press photos.

Value and legal notes

Replica prices for a 42 mm steel dive watch land between $200 and $600. Genuine Aquatimer Automatic prices on the secondary market run higher, and a service adds to that. US Customs can seize counterfeit goods under 19 U.S.C. 1526. Selling a replica as a genuine watch is trademark infringement.