Short answer
"Fake IW371736" means a counterfeit watch sold under the IWC reference number IW371736. That number sits in the IWC 3717 block, the block IWC used for the Pilot's Chronograph Automatic family: steel case, day and date at 3 o'clock, three subdials, and calibre 79320 inside. The exact dial color, strap, and production years of IW371736 I could not confirm from public records. Confirm the reference with IWC or an authorized service center before you pay.
What the genuine watch uses
IWC calibre 79320 is a Valjoux 7750 base, reworked in Schaffhausen. It runs at 28,800 vibrations per hour, has 25 jewels, and carries a power reserve of about 44 hours. Chronograph minutes sit at 12, chronograph hours at 6, running seconds at 9. The case is steel and about 42 mm across. The crystal is sapphire with anti-reflective coating. The movement sits inside a soft-iron inner cage that shields it from magnetic fields.
What the fakes use
Most replica IWC chronographs run an Asian 7750. Because that base is a 7750 clone, the subdial layout copies the genuine watch. Cheap builds use a 21,600 vph version, and the chronograph seconds hand sweeps less smoothly than the genuine 28,800 vph. Better builds use a 28,800 vph Asian 7750 and add engraved text on the rotor. No replica carries the soft-iron cage. None uses an IWC-serviced movement.
Tells to check
- Caseback: genuine engraving is crisp and shallow. Replica engraving is deeper and rounder at the edges.
- Day and date wheel: check the font, the centering, and the jump at midnight. Replica wheels sit low or off-center.
- Subdial hands: genuine hands reach the printed track. Replica hands stop short.
- Crystal: many replicas have anti-reflective coating on one face only. Most IWC references use coating on both faces.
- Crown and pushers: check thread pitch, feel, and the gap to the case.
- Weight: no soft-iron cage means less mass. A steel fake of the same size feels light in the hand.
- Lume: color and how long it holds after charging.
- Case thickness: replica 7750 cases run 1 mm to 2 mm thicker than the genuine watch.
Price signals
Replica IWC chronographs sell from about $200 to $1,000, based on movement and finish. Genuine used 3717-family watches trade for several thousand dollars. A "new" IW371736 at $600 is not a bargain. A seller with no box, no papers, and no service record is a risk.
How to verify a watch
- Ask for a caseback photo. Compare the reference number and serial to IWC's record.
- Ask for a movement photo. Rotor text and finish differ between IWC work and replica work.
- Have a watchmaker open the case. The 7750 base is visible, and the missing soft-iron cage is visible.
- Send the serial to an IWC service center. Staff can confirm the reference and serial pairing.
- Pay by a method that allows a chargeback, or use escrow.
Unknown: the exact dial, strap, and years of IW371736. IWC does not publish a full public archive of every reference. Treat a seller's spec sheet as unverified until a service center confirms it.