IW371772 falls in the IWC 3717 reference block. That block covers the Pilot's Watch Chronograph line. IWC built the 3717 from about 2006 to 2012. A fake IW371772 is a watch that copies the 3717 look but did not come from IWC Schaffhausen. The two digits after 3717 mark dial, strap, and market variants. IWC keeps no public list of every suffix. The dial and strap for a specific -72 unit needs confirmation from IWC or a watchmaker.

Genuine specs to compare

  • Case: stainless steel, 42 mm wide, about 14.5 mm thick
  • Movement: IWC caliber 79320, based on the Valjoux 7750
  • Jewels: 25. Rate: 28,800 vibrations per hour
  • Power reserve: 44 hours
  • Functions: hours, minutes, small seconds at 9 o'clock, 30-minute counter at 12, 12-hour counter at 6, day and date at 3
  • Crystal: sapphire with an antireflective coating
  • Water resistance: 6 bar
  • Magnetic shield: soft-iron inner case
  • Caseback: solid steel, engraved with the reference and case serial

Where copies differ

Most copies use a Valjoux 7750 clone made in Asia. Some use a quartz module with dead subdials. The IWC caliber 79320 carries IWC engraving on the rotor and bridges, plus a finish that clones do not match. The soft-iron inner case is one more part that copies leave out. Crystals on cheap copies are mineral glass. Case edges on copies look softer, and the crown and pushers have a looser feel.

Checks on a suspect watch

  1. Open the case. Look at the rotor engraving and the caliber number.
  2. Read the caseback. The reference number, the case serial, and the words Probus Scafusia sit in sharp, even type.
  3. Check the dial print. The IWC name and Schaffhausen sit in fixed spots. Copies shift the text or use thicker strokes.
  4. Compare the day and date font with a photo of a known genuine watch. Copies use wider or shorter digits.
  5. Test the chronograph. Start, stop, and reset are crisp on a 79320. Cheap copies lag or drag.
  6. Hold the watch. A steel 3717 has mass. Copies with plated cases and quartz movers feel light.
  7. Look at the lume. Compare the color and brightness with a photo of a genuine dial.

Copy tiers and prices

Copies come in three tiers. The low tier uses quartz or a basic mechanical movement, mineral glass, and printed subdials. The mid tier uses an Asian 7750 with a working chronograph. The top tier copies the case profile and dial markings with more care. No tier carries the IWC caliber 79320 or the soft-iron inner case. Prices run from tens of dollars to several hundred.

Questions for a seller

  • Which movement, and who made it?
  • What crystal material?
  • Measured case diameter and thickness?
  • Water resistance test result, and from which shop?
  • Return window and payment method?

What cannot be confirmed

No public IWC database lists the dial and strap for IW371772. IWC service records cover watches that owners sent in for repair. Photos on a listing show the outside of a watch, not the movement. A watchmaker with the case open gives the clearest answer.