Quick Answer
A fake copy of IW376073 is a counterfeit of the IWC Aquatimer Chronograph reference IW376073. It copies the case shape, dial layout, bezel scale, and case back text. It does not copy the movement, materials, finishing, or quality control. Counterfeits of this reference come in three grades: quartz copies, low-grade mechanical copies, and higher-grade copies built around a Chinese clone of the ETA 7750 chronograph. The genuine watch uses IWC calibre 79320 and carries a serial number tied to the reference, factory service records, and a manufacturer warranty. A counterfeit carries none of these and cannot be serviced by IWC.
What the Genuine Reference Should Show
Pull the official specification from IWC before you look at any watch. Confirm these points for the exact reference:
- Case diameter, thickness, and lug width in millimeters
- Movement calibre, jewel count, and power reserve
- Water resistance rating and crown construction
- Crystal material and coating
- Case back engraving layout and text
- Strap or bracelet type and any quick-change fitting
Counterfeit sellers list approximate numbers. A mismatch of one millimeter in diameter or thickness is a strong signal. Measure, do not eyeball.
Prerequisites
- Digital calipers reading to 0.01 mm
- Scale accurate to 0.1 g
- 10x jeweler loupe
- Bright diffused light and a clean matte surface
- Photos of an authentic example from a dealer listing or auction archive
- A return policy in writing from the seller
Step-by-Step Authentication Checks
- Confirm the reference number against the specification IWC publishes for the model.
- Measure case diameter, thickness, and lug width with calipers and compare each figure to spec.
- Weigh the watch head on a scale and compare. Copies use thinner cases and hollow parts, so mass runs low.
- Examine dial printing under 10x magnification. Genuine text has sharp edges, applied polished indices, and lume sitting level inside its frame.
- Check the date aperture. The window aligns with the dial, and the disc font matches the reference. Oversized or off-center numbers point to a clone.
- Inspect the hands. The sweep hand, subdial hands, and counterweights sit at the correct height and carry the correct finish.
- Rotate the internal bezel through its full range. The genuine SafeDive coupling moves the bezel in one direction with firm detents.
- Start, stop, and reset the chronograph several times. Pushers should have short travel, no grinding, and the reset should snap the seconds hand to zero.
- Read the case back text with the loupe. Compare font weight, letter spacing, and engraving depth. Fakes use shallow laser etching.
- Inspect the movement through a display back for IWC finishing, rotor engraving, and the calibre marking. On a solid back, request macro photos before payment.
- Work the crown and pushers. Threads engage without wobble and the crown seals against the case tube.
- Match the serial number to the case back engraving and the paperwork, then ask IWC or an authorized dealer to confirm the number against the reference.
- Send the watch to a watchmaker with IWC experience. Opening the case confirms or rejects the movement in minutes.
Red Flags
- Seller refuses macro photos of the dial, case back, or movement
- Price far below the market range for the reference
- Serial number missing, repeated across listings, or mismatched to the paperwork
- Caseback text with uneven spacing or blurred characters
- Chronograph pushers that wobble or a reset that stops short of zero
- No serialized warranty card and no service history
Legal and Practical Risk
Trafficking in counterfeit goods is a federal crime in the United States under 18 U.S.C. Section 2320, and U.S. Customs and Border Protection seizes counterfeit watches at the border. A buyer gets no manufacturer warranty, no service, and no genuine parts. Many independent watchmakers refuse to work on a counterfeit because replacement parts do not exist. Resale of a counterfeit is illegal and exposes the seller to civil liability. For the IW376073 itself, buy only from a seller who supplies the serial number, original documentation, and an inspection period, and confirm the reference before money changes hands.