Quick answer

Fake IW371642 watches exist in large numbers. Three checks catch most of them: the movement, the dial print, and the caseback engraving. Run those three first. Then check the case finish, the weight, and the paperwork. A genuine watch passes every check. A replica fails at least one.

Which watch the reference covers

IW371642 belongs to the IWC Portugieser Chronograph line, reference family 3716. The 3716 case measures 40.9 mm across and about 12.6 mm thick. The dial carries two subdials, small seconds at 6 and chronograph minutes at 12. The last two digits of an IWC reference mark the variant, so dial color, strap, and production years differ between numbers. Pull the reference from IWC's catalog and match the dial color and strap to it. A seller who cannot name the variant is a risk.

Movement

Most 3716 watches made after 2020 use IWC caliber 69355. It runs at 28,800 vibrations per hour with a 46 hour power reserve. Earlier 3716 and 3714 watches used caliber 79350, built on a Valjoux 7750 base at 28,800 vph. Replicas most often use a Chinese clone of the 7750 or a quartz module. Tell them apart in four steps.

  • Look through the caseback if it is sapphire. A 69355 shows a column wheel, a skeleton rotor, and striped bridges. Clones show stamped plates and no column wheel.
  • Start the chronograph and reset it. A 7750 based movement snaps back with force. A quartz module jumps.
  • Listen to the rotor. A 7750 family movement spins with a rattle. A 69355 winds with a pawl system and runs quieter.
  • Pull the crown and watch the small seconds at 6. Ask for a video that shows the crown position and the hand together.

Dial and print

Look at the printing with a loupe or a phone macro shot. Genuine IWC dial print is raised and even. Replica print shows ragged edges, filled counters, and letters that touch. Check these points:

  • The IWC logo sits level with the dial center line.
  • Arabic numerals are applied on most variants, with sharp corners and a clean step at the dial surface.
  • The text height of the IWC mark matches the text height of the Schaffhausen line below it.
  • The subdial rings are cut, not printed. Run a fingernail across one. A print shows no step.
  • The date window edges are beveled on the inside.

Case, crystal, and finish

Look at the line between polished and brushed surfaces. Genuine finishing shows a sharp edge. Replica finishing shows a soft, rounded edge. Run a fingertip along the lug edges. Genuine edges feel crisp. Copies feel soft. On the crystal, look for a faint blue or purple tint at an angle. That tint comes from anti-reflective coating. Many copies carry coating on one face, or none.

Caseback and serial

Engraving on a genuine caseback is deep and sharp, with even depth across the letters. Replica engraving is shallow and shows a wide bevel from the laser cut. Compare the serial on the caseback with the serial on the warranty card. They should match. Ask IWC service to confirm the serial and the reference before you send money.

Weight and size

Ask the seller for a weight and a caliper reading. The case should read 40.9 mm across. Copies often read 41.5 mm or 42 mm. Compare the weight against a known genuine example of the same variant. Copies often land 10 to 20 g off.

Box, papers, and price

Replica sellers copy boxes and booklets, so paperwork proves little on its own. Check the dealer stamp, the warranty card, and the serial. A replica sells for a few hundred dollars. A genuine IW371642 trades in the thousands on the secondary market. A genuine watch offered at 15 percent of market price is not a bargain.

Red flags

  1. Stock photos only, no dated photo of the watch in hand.
  2. Serial on the caseback does not match the warranty card.
  3. Pushers feel mushy or the reset is slow.
  4. Dial print shows filled letters under magnification.
  5. Price sits far below the market range for the same variant.
  6. Seller refuses a video call with the watch running.

US legal note

Importing a counterfeit watch into the US violates 19 U.S.C. 1526 and 18 U.S.C. 2320. Customs can seize the watch and assess a fine. Selling a replica as genuine carries fraud exposure in US jurisdictions.

Known gaps

IWC does not publish production counts by variant. The full dial and strap set for IW371642 needs confirmation from IWC records. Ask IWC service before you buy.