Short Answer

IW371790 is a reference number that Chinese replica sellers attach to an IWC Portugieser Chronograph. I could not match that exact number to a current entry in IWC's public catalog. The documented Portugieser Chronograph references sit in the IW3716xx range, for example IW371604, IW371609 and IW371617. Treat IW371790 as a seller label. A replica with that label copies the 41 mm Portugieser Chronograph case, the two-register dial, and the layout of caliber 69355. It is not made by IWC. In the United States, importing or reselling it is against federal law.

Specs of the Watch Being Copied

  • Case: 41 mm stainless steel, 13.1 mm thick, 30 m water resistance.
  • Movement: caliber 69355, in-house automatic chronograph, column wheel, 46 hour power reserve.
  • Dial: two subdials, small seconds at 6, 30 minute counter at 12, date window at 3.
  • Crystal: sapphire with antireflective coating on both faces.
  • Strap: alligator leather on a pin buckle, or steel bracelet on some references.
  • US boutique price: about $8,000 to $8,800 on leather. Gold cases and bracelets cost more.

Replica Tiers and Prices

Listings from China fall into three groups.

  1. Low tier, $80 to $150. Quartz movement, mineral glass, printed dial.
  2. Mid tier, $200 to $400. 7750 based automatic, sapphire glass, steel case.
  3. High tier, $400 to $700. Sellers call these super clones. They use a movement built to mimic the 69355 layout.

Points That Show the Difference

  • Subdial spacing. Genuine registers sit at set distances from the center. Clones shift them a millimeter or two.
  • Movement. A 7750 base winds in one direction and freewheels in the other. The 69355 winds both ways. A display back shows the rotor behavior.
  • Date font. Genuine date wheels use tall thin numerals. Clones use thicker type and a window that sits off center.
  • Case finishing. Genuine brushing and polishing meet at a sharp line. Clone edges are soft.
  • Weight. A clone steel case uses thinner walls and weighs less than the genuine part.
  • Caseback text. Genuine engraving is laser cut and shallow. Clones stamp deeper.

Shipping and Payment

Transit from China to the US runs 7 to 21 days. Payment goes through bank transfer, crypto, or card processors that rotate domains. Chargebacks are rare because the receipt lists a different item. Customs seizure is the main risk. CBP can hold a package, send a notice, and destroy the watch. The buyer loses the goods and the money.

Legal Status in the US

  1. Import. 19 U.S.C. § 1526 bars import of goods that copy a registered trademark. CBP seizes the shipment.
  2. Criminal. 18 U.S.C. § 2320 covers trafficking in counterfeit goods. A first offense carries up to 10 years in prison and a $2 million fine.
  3. Civil. 15 U.S.C. § 1117 lets a trademark owner recover statutory damages up to $2 million per counterfeit mark per type of goods when the use is willful.

One watch for personal use carries less legal exposure than reselling. The exposure is not zero. The parcel is still subject to seizure.

Checks on a Watch in Hand

  • Run the chronograph. A 7750 base feels stiff at the start of the pusher travel.
  • Watch the date change. It should flip within 10 minutes of midnight.
  • Measure the case across, crown excluded. Genuine size is 41.0 mm.
  • Time it over a week. A regulated 69355 holds within a few seconds per day. Clone movements drift further.
  • Read the rotor. IWC rotors carry the Probus Scafusia mark and the jewel count.

Repair is the other cost. No IWC service center will touch a counterfeit, and independent watchmakers often decline the work because parts do not fit.