The short answer

An IW376087 offer that undercuts the established secondary market for a complete set is a counterfeit until proven otherwise, and once it ships your money is gone. The reference number is not a product, it is an identifier, and sellers of fakes print it on cases that share almost nothing with the watch IWC built. Buy from a seller who will show a serial number, matching caseback engraving, service records, and a working return window, and walk away from anyone who photographs the dial only, refuses a movement photo, or prices the watch as if the reference did not matter.

What the reference number actually tells you

IWC reference numbers in the 376xxx block belong to the Aquatimer family of dive chronographs, a line defined by screw-down crowns, rotating dive bezels, and chronograph pushers rated for water exposure. Before paying for any specific reference, confirm the case diameter, lug width, water resistance rating, movement caliber, and crystal type against IWC's own reference documentation. Counterfeit listings lean on vagueness here, quoting dimensions and ratings that do not match the genuine article, and a buyer who never checks the source specification has nothing to compare the watch against when it arrives.

Checks that separate a genuine watch from a fake

• Caseback engraving: reference, serial, and material stamps should be crisp, correctly spaced, and consistent with the case metal.
• Movement photo: ask for a clear image through the caseback or of the movement itself. Fakes rarely survive close inspection of finishing and rotor engraving.
• Subdial alignment: chronograph registers should be centered in their apertures, with matching hand lengths and no paint bleed.
• Dial printing: text weight, spacing, and font should be uniform. Fakes commonly show thick, crowded, or misaligned lettering.
• Bezel action: a dive bezel should rotate with firm, defined clicks and align exactly at twelve.
• Crown and pushers: threads should engage smoothly, and pushers should return cleanly with no grit.
• Papers and history: box, booklet, warranty card, and service receipts should name the same serial as the case.

Parameter bands to expect

Use these as screening ranges only, and verify the exact figures for the reference you are considering, because IWC has revised this family across generations.

• Case diameter: commonly in the low to mid 40 mm range for this line, with some variants larger.
• Lug width: typically 22 mm class on a steel bracelet or rubber strap.
• Water resistance: dive-watch territory, meaning a screw-down crown and caseback are mandatory, not optional.
• Crystal: sapphire, usually with anti-reflective treatment on at least one surface.
• Movement: automatic chronograph with a modified base caliber, day or date display, and roughly two days of power reserve.

Pitfalls in the counterfeit market

The most common failure is a listing that sells a generic chronograph case with an IWC dial printed onto it. These watches often keep time for a while, then lose the date function, leak at the crown, or stop entirely, and no watchmaker will take them in for service because parts do not exist. A second pitfall is the bait listing: a genuine reference number and genuine photographs, followed by a different watch in the box. A third is the pressure tactic, where the seller demands a bank transfer, a messaging app, or a friends-and-family payment that removes your ability to dispute the charge. There is also a legal dimension. Trafficking in counterfeit trademarked goods is a federal offense in the United States, and imported counterfeit watches are subject to seizure, which means the buyer can lose both the watch and the money.

FAQ

Is a fake IW376087 water resistant like the real one?

No. Gaskets, case tolerances, and crown threading on counterfeit cases are not built or tested to a dive rating, even when the caseback is stamped with a depth figure. Wear one in the water and you risk a flooded movement.

Why do counterfeit listings use a real reference number?

Because buyers search by reference. The number gives the listing an appearance of specificity while the physical watch is a generic case with a copied dial, which is why photographs and provenance matter more than the number in the title.

Can a watchmaker service a counterfeit chronograph?

Usually not. Movements in counterfeit watches are often cloned or discontinued, and parts, gaskets, and technical documentation are unavailable, so a repair can cost more than the watch did.

What should I ask a seller before paying?

Ask for the serial number, a movement photograph, a written description of condition, and a return policy in writing. A legitimate seller answers all four without hesitation.