Short answer: The IW371704 is an IWC Pilot's Watch Chronograph with a 42 mm steel case and caliber 79320. Copies are common because the model sold in large numbers from about 2006 to 2012. The movement, the caseback engraving and the crown are the three places where most copies fail.
What the reference is
IWC built the 3717 family from about 2006 to 2012. That run replaced the older 3706 Fliegerchronograph and was replaced by the 3777 family. The IW371704 sits in the run with a black dial, a stainless steel case and a leather strap. The case measures 42 mm across and about 15 mm thick. Water resistance is 6 bar, or 60 m.
Inside is IWC caliber 79320. It is an automatic chronograph on a base ETA/Valjoux 7750, with 25 jewels, 28,800 vph and a power reserve of 44 hours. The layout is fixed: small seconds at 9 o'clock, a 30-minute counter at 12, a 12-hour counter at 6, and day and date windows at 3.
Case, dial and crystal checks
- Caseback: solid steel, screw-down. A genuine watch shows the reference IW371704 and a serial number cut into the metal. Copy engraving looks shallow and the font is off.
- Crown: signed, with crisp edges and a firm thread. Copies often show a soft logo and a crown that sits proud of the case.
- Dial: black with white luminous markers. Check the print with a loupe. Copy dials show thick text and uneven lume.
- Crystal: sapphire with anti-reflective coating. Mineral glass copies chip at the edge and show a different sheen.
- Pushers: start, stop and reset feel firm on a clean movement. This test alone does not prove anything.
Movement checks
Ask for a photo of the movement. The rotor on a genuine caliber 79320 carries IWC engraving and the caliber number. A stock Valjoux or ETA rotor is a copy. Case clamps, screw heads and the finish on the bridges are other tells. Serviced genuine movements show clean oil and no scratches on the rotor weight.
Papers, box and price
A full set has the box, the booklet and a guarantee card that matches the serial on the caseback. Used IW371704 watches sell in the region of $3,000 to $5,000 in US dollars. Condition, service history and a full set move the price. A new example at a few hundred dollars is a copy.
Verification
A watchmaker can open the case and confirm the movement in minutes. IWC service centers and independent watchmakers with a parts account can also check the serial. Photos alone do not settle the question. Details change between production years, so confirm specs against the watch in hand, not against a listing.