The short answer: a fake IW371619 is a copy of IWC's Portugieser chronograph reference, and the best replica you can buy is a clone-grade piece with a working two-register chronograph, a case profile matched to the genuine 41 mm silhouette, and dial printing that still reads clean under a jeweler's loupe. Judge any candidate on four things: case geometry and crystal, dial and hand finishing, chronograph movement behavior, and how much the seller is willing to show you before you pay. Sections below break those down, then compare the tiers.

What the genuine IW371619 actually is

The reference belongs to IWC's Portugieser chronograph family, a line built around a wide, thin-bezel case, applied numerals and markers, feuille hands, and a two-register dial layout with the chronograph minutes counter at 12 and running seconds at 6. Genuine current examples run an in-house automatic chronograph calibre from the 69000 series. IWC publishes case dimensions, movement data, and dial variants at the reference level, so confirm the exact configuration for IW371619 there before you compare anything, because dial colors, strap options, and case finishes change between markets and production years.

Criterion 1: case geometry and crystal

Portuguese cases are thin, wide, and softly curved, which is exactly where cheap copies fail. A good fake holds the correct lug-to-lug span, a bezel that sits nearly flush with the mid-case, and a lugs profile that tapers the way the original does in profile photos.

  • Signs it is done well: crown and pushers sit at the right height, caseback engraving is crisp rather than laser-fuzzy, sapphire shows a faint blue or colorless edge instead of a thick milky ring.
  • Signs it is not: sharp lug edges, a bezel that looks wider than the dial opening, mineral glass with visible distortion at the edges, or a case that feels light in a way steel should not.

Criterion 2: dial, hands, and sub-dial printing

Dial work decides whether a fake reads as a $200 copy or a serious build. Applied markers should throw a real shadow, the minute track should be printed fine and even, and the sub-dials should be recessed with snailed or matte finishing that differs from the main dial.

  • Check the hands: feuille hands should taper to a point, not a blunt wedge, and the polished bevel should catch light along the full length.
  • Check the text: brand and reference printing should be sharp at 10x magnification. Blurry or overly heavy text is the most common tell on mid-tier copies.
  • Check alignment: sub-dial hands should zero cleanly and the 12 and 6 markers should line up with the crown axis.

Criterion 3: movement and chronograph behavior

The chronograph is the hardest thing to fake well. On the genuine calibre the start, stop, and reset feel crisp, the seconds hand starts with little or no jump, and the minutes counter advances in clean steps. Clone-grade replicas use a column-wheel-style chrono module or a reworked automatic chrono, and the good ones behave the same way.

  • Red flag: a quartz movement hidden behind a fake rotor, which shows as a seconds hand that ticks.
  • Red flag: a pusher that feels spongy, a reset that stutters, or a minutes counter that drifts out of sync.
  • Red flag: a rotor that spins for a second and stops, or winding that feels gritty within half a turn.

Criterion 4: seller transparency and QC photos

Ask for timegrapher numbers, close-ups of the dial text, the caseback, and the clasp, plus a short video of the chronograph running and resetting. A seller who will not send those before payment is not worth the risk. Also weigh where you are: counterfeit watches are illegal to import into the US and many other countries, and customs seizures do happen, so understand the exposure before you order.

Option comparison: clone grade versus mid tier

Clone grade, functional chronograph

  • Pros: correct sub-dial function, closer case profile, better dial finishing, serviceable movement in many cases.
  • Cons: higher price, longer wait, more variation between individual units, so QC matters more.

Mid tier, decorative or simplified chronograph

  • Pros: lower cost, faster shipping, adequate for someone who wants the look on a wrist and will not study the dial.
  • Cons: sub-dials may not function, printing is softer, case proportions drift, and the watch tends to read as a copy from arm's length.

Which one to pick for your use case

If you want a watch you can wear daily and hand to a friend without thinking twice, go clone grade and spend your effort on QC photos, not on the lowest listed price. If you want a visual stand-in for occasional wear and you accept the trade-offs, mid tier is the honest choice. If you want the real thing, a pre-owned IW371619 is the route that holds value, and listing data from the pre-owned market will tell you what that costs today.