Judge a fake IW371490 against the real reference, not the seller's description. The genuine watch is a 40.9 mm steel Portugieser Chronograph, 12.3 mm thick, with chronograph minutes at 12, running seconds at 6, a date at 3, and IWC calibre 69355 inside. A replica that misses case height, subdial spacing, or date position fails before dial print matters. Confirm those three points first, then judge finishing, strap, and how the chronograph feels when you start, stop, and reset it.
What separates a good fake IW371490 from a poor one
Replica quality on this reference splits into three rough tiers. Entry builds use a 7750 based movement in a case that runs tall or wide, with subdials placed by a dial overlay. Mid tier builds copy the case dimensions and use a modified 7750 with a decorated bridge. Top tier builds match 40.9 by 12.3 mm, use a chronograph module that engages without play, and get the date font and window cut close to the original. Pay for the top tier only when the seller shows a macro of the date window, a timegrapher readout, and a clear photo of the caseback engraving.
What to look for
- Case: polished bezel ring, brushed flanks, downward lug curve. Measure thickness at the lugs, not the middle of the crystal.
- Dial: sharp print on the IWC Schaffhausen signature, correct placement of AUTOMATIC above the 6 subdial, snailed finish inside both subdial rings.
- Hands: gold plated leaf hands that reach the minute track. Short hands are a common shortcut.
- Crystal: sapphire with anti reflective coating on both faces. A strong blue tint points to single sided coating.
- Caseback: crisp engraving depth, clean thread engagement, correct reference text.
- Strap: 20 mm lug width, tight stitching, buckle pin shape that matches the original profile.
- Crown and pushers: crown sits flush with no wobble, pushers travel with even resistance, reset snaps back in one motion.
Parameter bands to compare
Use these bands when you read a spec sheet or measure the watch in hand. A number outside the band points to a different case or to a stock photo listing.
- Case diameter: 40.7 to 41.2 mm.
- Case thickness: 12.0 to 12.8 mm. Under 12 mm suggests a shallow caseback, over 13 mm sits tall on the wrist.
- Lug width: 20 mm, within 0.2 mm.
- Beat rate: 28,800 vph. A 21,600 vph movement is a downgrade on this reference.
- Power reserve: 40 hours or more on a full wind.
- Timegrapher rate: within about 15 seconds a day in either direction is workable for a replica. Ask for the reading before you pay.
- Amplitude: 270 to 310 degrees on a full wind.
Where replicas of this reference go wrong
- Photos taken at an angle to hide case thickness.
- Date window kept in shadow so the font and frame are unreadable.
- Rotor photos that cover the balance and the chrono mechanism.
- Listings that quote 1:1 without any dimensions.
- Caseback stickers left on to hide engraving quality.
- Sellers who will not send a short video of the chronograph starting, stopping, and resetting.
Movement questions to ask before paying
Calibre 69355 is an IWC manufactured automatic chronograph with a 46 hour power reserve, so a replica that claims a true clone needs proof. In most cases the movement is a modified 7750 with a decorated bridge. Ask which base movement is inside, ask for a photo with the rotor turned aside, and ask for a fresh timegrapher print. A seller who answers all three is easier to trust than one who sends a catalog photo.
Fake IW371490 Review: The Batch Worth Buying
FAQ
Will a fake IW371490 fool a watchmaker?
No. Caseback finishing, engraving depth, date font, and pusher feel give it away on a bench under a loupe.
Is a clone of calibre 69355 available?
Sellers advertise one, but most examples are 7750 based movements with a decorative plate. Ask for a clear photo of the balance and the chronograph levers.
Do box and papers prove quality?
No. They prove the seller spent money on packaging. Judge the watch, the measurements, and the movement behavior.
What is the biggest tell on the wrist?
Case thickness and date position, then subdial spacing. Those three read from across a table.
Should I pay more for Swiss made markings?
No. The marking is a copy of a Swiss label, not evidence of Swiss production. Spend the difference on a better case and a tested movement.