The short answer
IW371734 is an IWC chronograph reference number. No replica of it is the real thing, and a seller who claims otherwise is lying to you. What you can actually judge is how closely a replica copies the case, the dial, and the feel on the wrist, plus whether the seller is straight with you about the movement inside. That is the entire game.
What the reference number points to
IWC has used the 3717 block for steel chronographs since the mid-2000s. Family traits: a case in the 41 to 42 mm range, sapphire crystal, and a chronograph movement built on the ETA/Valjoux 7750 architecture. IWC's 79320 and 79350 calibers are both 7750 derivatives, reworked with the brand's own finishing, rotor, and regulation.
Before you compare anything, pull the reference up on IWC's own site. Numbers get reused across catalog years and collections, and dial layout can shift between them. If a seller's photos do not match the official specs, that tells you plenty on its own.
Why this reference gets copied so heavily
Two reasons. The dial is clean. There is no moonphase and no perpetual calendar, nothing that has to be hand-finished to read correctly at arm's length. The case is also a simple round shape with straight lugs, which is far easier to machine than a tonneau or a cushion.
The catch: simple is not the same as easy. A plain dial shows every flaw. Subdials sitting a hair off-center, a date aperture cut low, indices at slightly different heights. All of it is visible in a way it would not be on a busy dial.
What I inspect first on a replica
- Case width and thickness. Chronographs in this family run thick, typically 13 to 15 mm. Replicas often arrive a millimeter thin, which changes the whole profile.
- Lug to lug. This is the measurement that decides whether it wears well on your wrist. Ask for it.
- Pushers and crown. They should give a defined click. Mushy pushers usually mean a low-grade 7750 clone or a quartz movement behind a decorated plate.
- Subdial position. On a 7750-based watch the layout is fixed by the movement. Wrong placement means the architecture inside does not match the original.
- Dial printing. Font weight, letter spacing, and depth of the applied indices. Cheap replicas print the logo flat instead of applying it.
- Crystal. Sapphire with a colorless anti-reflective coating. Glass that throws purple or blue at an angle is a cheap coating, or mineral glass.
The movement, stated plainly
Almost every replica of a 7750-based chronograph runs an Asian 7750 clone, usually Seagull or Shanghai. It works. It winds, it chronographs, it keeps time well enough. That is exactly why these watches feel convincing on the wrist.
What it is not is a finished IWC caliber. No hand-applied striping, no rotor with the same engraving depth, no factory regulation to a tight spec. A quartz replica is a different problem entirely: the seconds hand ticks, and the chronograph hand snaps back to zero in a way a mechanical one never does.
Strap, clasp, and the details buyers skip
Lug width matters more than most people think. If the strap is 20 mm when the case calls for 21 mm, you will see a gap at the lugs and no aftermarket strap will ever fit properly. Check the clasp engraving depth and the edge finishing too. Folded steel with sharp edges is the giveaway on an otherwise decent watch.
The legal side nobody mentions
Counterfeit watches are illegal to import into the United States. U.S. Customs and Border Protection seizes them, and the buyer usually eats the loss when a package gets stopped. Trademark holders can pursue sellers as well. So "1:1" and "AAA" are marketing terms, not legal descriptions, and no seller can change that.
Quick checklist before you buy
- Verify the reference on IWC's site first, so you know what you are comparing against.
- Ask for case diameter, thickness, and lug to lug, measured in millimeters.
- Ask what movement is inside, by name.
- Request macro photos of the dial, caseback, and clasp.
- Read the return policy. If there is not one, that is your answer.
A replica of this reference can look good on a wrist. It will not be an IWC, and the seller who tells you otherwise is the one to walk away from.