If you are shopping for a fake IW3717, the version worth your money is the one built on a 7750 family chronograph movement inside a case that matches the dimensions IWC publishes for your reference number. That is the top pick, and it sets the benchmark for everything below. The reason is plain: this family, the Portugieser Chronograph, uses a vertical dial layout with the chronograph counters stacked at 12 and 6, and that layout only sits right when the movement underneath has the correct diameter and counter positions. A sharp dial on the wrong movement case looks wrong from across a table. The criteria that decide the purchase are movement, case and crystal, dial and date, strap and finish, and the quality control evidence a seller will actually show you.

Movement: Swiss 7750 against an Asian 7750 clone

Both options place the subdials correctly because both follow the same architecture. What separates them is the consistency of the chronograph action, how easy the watch is to service, and how it holds up over years of wear.

Pros

  • Swiss 7750 builds start, stop, and reset with a firm, even pusher feel.
  • The running seconds at 9 and the 30 minute and 12 hour counters mirror the original platform.
  • Any competent watchmaker can service it, and parts are not exotic.

Cons

  • A Swiss movement build costs more, and some sellers swap in a clone after the photos are taken.
  • Clone movements can run well but vary between batches, so two watches from one listing may not feel alike.
  • No movement choice fixes a bad case, and none of them make the watch genuine.

Best for: buyers who wear the watch often and want a working chronograph should take the Swiss 7750 tier. A clone makes sense when the watch lives in a box and the price reflects that.

Case and crystal: the numbers you can verify

Ask for caliper photos. You want case diameter across the bezel, total thickness, and lug width, then compare those numbers with the spec sheet IWC publishes for the reference you are copying. Thickness is the fastest tell, because a thin case over a thick movement forces either a domed caseback or a crystal that sits too high.

Pros

  • Correct diameter keeps the bezel thin and the dial wide, which is the whole point of this design.
  • Anti reflective coating on both faces of the crystal cuts glare and lets the dial read clean.
  • A well fitted caseback sits flush and does not rock under your thumb.

Cons

  • Many listings quote dimensions pulled from a different reference in the same family.
  • Coating claims cannot be confirmed from photos.
  • Water resistance figures on replicas are decoration. Do not swim with one.

Best for: anyone who intends to wear the watch with short sleeves. If the seller will not measure the case, treat the listing as unknown rather than assume it is correct.

Dial, hands, and date

The dial is what you look at all day, so small faults here become the ones you notice most.

  1. Confirm both counters sit on a vertical line through the center, with the date window at 3.
  2. Check the hands: leaf shape, thin at the base and pointed, even polish, no tool marks.
  3. Study the numerals and printing. Thin, washed out printing is the usual fault.
  4. Look at date alignment inside the aperture. A date sitting high or low is a frequent flaw.
  5. Angle the dial under a lamp and check the counter rings for even graining and crisp small text.

Best for: daily wearers who will stare at the dial. If a seller will not send a straight on, full resolution dial photo, that listing is not for you.

Strap, clasp, and case finish

Finish is the part photos hide. Replicas often brush the case well and finish the clasp poorly, or the reverse.

Pros

  • An alligator grain strap with a signed deployant lifts the watch more than a movement upgrade does.
  • Even brushing on the lugs and polished flanks catch light the way the original does.
  • Sharp lug edges and clean crown engraving suggest a factory that paid attention.

Cons

  • Gold tone plating wears through at the clasp and crown within months.
  • Stiff, glossy straps on cheap builds never soften.
  • Spring bars that are not truly threaded strip the first time you change the strap.

Best for: steel case versions. If you want a gold look, accept that the plating is the first part to fail.

Seller QC and what the listing proves

You are not buying a photo from a catalog, you are buying one watch. The evidence should point at that one watch.

Pros

  • Timegrapher photos with rate and amplitude, plus a video of the chronograph starting, stopping, and resetting.
  • Reference specific photos instead of the same stock images reused across a whole catalog.
  • A stated return window and a clear policy on movement swaps.

Cons

  • '1:1' and 'super clone' labels mean nothing on their own.
  • Sellers who reply with catalog pictures rather than your unit.
  • No order number or QC tag tying the photos to what you paid for.

Best for: first time buyers. Ask for QC photos of the exact piece and confirm your order number appears in the frame.

Five minute check when the watch arrives

  1. Wind it and let it run an hour. Compare the rate against a phone clock.
  2. Run the chronograph three times. Reset should snap back to zero on both counters together.
  3. Check that the date flips near midnight and lands centered in the window.
  4. Hold the dial under a lamp at an angle and look for dust, scratches, or a hazy crystal.
  5. Feel the crown for wobble and confirm the caseback and lugs sit flush.
  6. Match the strap and clasp against the photos you approved.

Which build to choose

For regular wear, take the Swiss 7750 tier in a case that matches the published dimensions, in steel, with a decent strap. For a watch that stays in a case and comes out a few times a year, an Asian 7750 build with a strong dial is enough, provided the price sits well below the Swiss tier. Skip any listing where the seller cannot produce caliper measurements, a timegrapher reading, and a straight on dial photo. Those three items cost nothing to make, and their absence tells you what the rest of the transaction will look like.