Judge the replica IW371620 on three things: the subdial layout, the case dimensions, and whether the seller shows real photos of the actual watch. The genuine IWC Portugieser Chronograph ref. IW371620 runs a 41 mm steel case at roughly 13 mm thick, with running seconds at 6 o'clock, a chronograph minute counter at 12, and no date window. Any listing that misses one of those points is selling you a different watch with the right model number pasted on top. Marketing phrases like "1:1 super clone" or "Swiss made" carry no information. Photographs, measurements, and movement details do.
What the IW371620 Actually Is
The reference is a steel Portugieser Chronograph with a silver-plated dial, gold-plated appliques and leaf hands, two subdials, and a slim bezel. IWC builds it around the in-house calibre 69355, a column-wheel chronograph with a 46-hour power reserve, shown through a sapphire exhibition caseback. Water resistance is rated at 3 bar, which is splash resistance only. There is no date, no day, and no tachymeter. Those five facts filter out most mislabeled listings before you ever look at a photo.
What to Look For
Subdial layout
This is the single biggest tell. Genuine: small seconds at 6, chrono minutes at 12. Many low-cost replicas hide a Valjoux 7750 derivative under the dial, which naturally puts running seconds at 9 and the chrono counter at 6 or 12. Sellers work around this with modified plates or by faking one subdial entirely. Ask for a video with the chronograph started and stopped. The hand at 12 should advance one step per minute, and the hand at 6 should sweep smoothly at all times.
Case size and thickness
Measurements separate honest sellers from photo thieves. A 41 mm case at 13 mm is the target. Anything at 14.5 mm or taller is a stack of movement plus module, and it will sit on the wrist like a different watch. Lug width should be 20 mm.
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Caseback and movement finish
The genuine watch has a sapphire back showing the 69355 with its column wheel and the Probus Scafusia engraving on the rotor. Replica backs show either a decorated 7750 rotor or a printed plate. Look at the shape of the bridges, the finish on the screws, and whether the rotor text is engraved or stamped. Blurry macro shots are a refusal, not a limitation.
Dial printing, hands, and strap
Applied numerals should sit flat and reflect light evenly. Printing should be crisp at macro distance, particularly the Schaffhausen line. Hands should be polished with no tool marks. Genuine straps are alligator; replicas are usually embossed calf, which is acceptable if the seller says so and prices it as such.
Parameter Bands
- Case diameter: 41 mm. 40.5 to 41.5 mm is within measurement error. Anything 42 mm or more is a different reference.
- Case height: about 13 mm genuine. 13.5 to 14 mm is fine on a good build. Over 14.5 mm, expect top-heavy wear and a thick caseback.
- Lug width: 20 mm. Confirm before buying spare straps.
- Movement: column-wheel chronograph or a close clone. A stock 7750 without relocation work is a downgrade, not a replica.
- Water resistance: 3 bar claimed on both. Treat any replica as splash only.
- Chronograph action: crisp pusher start and stop, instant reset to zero. Sluggish reset points to a worn or cheap cam.
Pitfalls That Cost Buyers Money
- Stolen photos of a genuine watch. Ask for a dated photo or a short video with the chronograph running.
- Listings that show a date window. The 371620 has none.
- "Swiss made" claims on a watch assembled in Asia. Movement origin and assembly origin are separate facts.
- Untested water resistance. A gasket that was never pressure tested will fail in a sink, not just a pool.
- No service path. Non-standard movements mean a local watchmaker may refuse the job, and parts may not exist in two years.
- Customs risk. Counterfeit goods are subject to seizure at the U.S. border, and the shipment is your loss, not the seller's.
- Resale expectations. A replica cannot be legally sold as genuine, and it has no collector market value.
Questions Buyers Ask
Is buying a replica legal in the US?
Owning one is not the issue. Importing counterfeit trademarked goods is prohibited and shipments can be seized and destroyed. Selling a replica while presenting it as genuine is fraud. Understand that before you order from an overseas seller.
Will a replica fool an authorized dealer?
Usually not under a loupe. The caseback, movement finish, and hand polish give it away fast. It may pass at arm's length in a restaurant, which is the realistic bar.
Can I get a replica serviced?
Sometimes, at an independent watchmaker who works on Asian movements. IWC will not touch it, and authorized service centers may refuse the watch outright. Budget for a full movement swap rather than a repair.
Can I swim with it?
No. Even the genuine watch is rated 3 bar. Seals on a replica are rarely tested and often dry from storage.
Does box and papers matter?
Only for resale, which is not a realistic option. It does tell you the seller handles complete sets, which is a mild signal about organization rather than quality.
Before You Pay
- Confirm the reference details: 41 mm, no date, seconds at 6, chrono minutes at 12.
- Request photos and a video of the exact unit, with the chronograph started and reset.
- Ask for a caliper reading of diameter and thickness.
- Ask which movement is inside and whether it is a column wheel design.
- Confirm the return window and who pays return shipping.
- Use a payment method with chargeback protection. Wire transfers and crypto remove your leverage.
- Assume customs risk is yours and plan accordingly.