If you are searching for a fake IW371618, the honest answer is that no counterfeit sold under that reference matches the genuine IWC Portugieser Chronograph in the details that decide value, and most of them fail at the case back within seconds of an inspection. The IW371618 sits in the 3716 family: a 41 mm stainless steel Portugieser Chronograph built around the in-house calibre 69355, a column wheel chronograph with a 46 hour power reserve and a sapphire display back. The useful move is to learn the tells, then buy a genuine example from a source that stands behind the serial number.
Why this reference attracts counterfeiters
The Portugieser Chronograph has a clean dial with two subdials at 12 and 6 and a date at 3, so the design does not depend on complex printing that a low cost factory would struggle to reproduce. That makes the outside easy to approximate. It also means the giveaway is mechanical: the movement, the pusher feel, the finishing on the bridges, and the engravings on the case back.
What to look for before you pay
Case back and movement
A genuine 3716 family watch has a sapphire display back showing calibre 69355. You should see Geneva stripes, a column wheel, and a signed rotor. Most counterfeits use a solid back or a printed decoration plate. If the seller will not photograph the movement with the serial visible, stop there.
Dial and hands
Indices are applied metal, not printed. The subdial rings sit level with the dial. The date window is crisp with no fuzzy printing. Hands are polished, and the chronograph seconds hand resets to 12 without wobble.
Case, weight, and pushers
Expect a sharp bezel edge, straight lugs, and a crown that threads down with no grit. Pushers have a short, firm travel and no grinding. A counterfeit feels light and hollow in the hand, and the pushers feel spongy or stiff.
Papers and serial
Ask for the warranty card, the original invoice, and service history. The serial on the case back should match the paperwork. IWC lets owners register the watch for an extended warranty, a check a counterfeit cannot pass.
Measurable bands for the real watch
- Case diameter: 41.0 mm, measured across the case without the crown.
- Case height: about 13.0 mm including the crystal.
- Lug width: 20 mm. That is narrow for a 41 mm case, and a common tell when a copy uses 22 mm lugs.
- Water resistance: 3 bar, so 30 meters. A listing claiming 100 meters is not this reference.
- Power reserve: 46 hours on a full wind.
- Weight: a steel head on a leather strap lands near 80 grams. A copy comes in lighter.
Pitfalls to avoid
- Listings with studio photos only and no movement shot.
- Sellers who price far under the market and push for a bank transfer.
- "Super clone" claims. The phrase means nothing, and the movement inside is a low grade automatic.
- A closed case back on a reference that should have a display back.
- Missing serial engraving, or a serial that does not match the card.
- Seizure, duty, and chargeback risk when counterfeit goods cross a border.
FAQ
Is a fake IW371618 ever a good buy?
No. You get no warranty, no service support, and almost no resale value. The legal risk of importing counterfeit goods is yours as well.
How much should a genuine IW371618 cost?
Check current dealer and pre-owned listings for the number that day. Pricing moves, so compare at least three sources before you commit.
Can a jeweler tell the difference?
Yes. Once the back is open, the movement decides the question. A watchmaker who services IWC can confirm it in minutes.
Where should I buy instead?
An authorized dealer, or a pre-owned seller with a written return policy and a documented service history.