Short answer
The IW371445 is an IWC Portugieser Chronograph. Genuine examples use a stainless steel case 40.9 mm wide and 12.3 mm thick, a Calibre 79350 movement, and a convex sapphire crystal. Most fakes fail one of three checks: case height, dial printing, or the movement. Replicas run 14 mm to 15.5 mm thick and use an Asian copy of the Valjoux 7750.
What the reference is
IWC built the IW371445 inside the Portugieser Chronograph 3714 family. Core specs:
- Case: stainless steel, 40.9 mm diameter, 12.3 mm height
- Movement: Calibre 79350, base Valjoux 7750, 31 jewels, 28,800 vph, 44 hour power reserve
- Dial: silver plated, applied indices, hands and appliqués plated in gold
- Layout: small seconds at 6, 30 minute counter at 12, date at 3
- Crystal: convex sapphire with antireflective coating on both faces
- Water resistance: 3 bar (30 m)
- Strap: alligator leather with a steel pin buckle or folding clasp
IWC used the 3714 block for several dial colors and metal versions. Confirm the dial and strap for the exact watch in front of you. Details you cannot confirm should be checked with IWC before purchase.
Check 1: case height and profile
Measure the case with a caliper. Genuine height is 12.3 mm. Copies with an Asian 7750 and a thick case back land at 14 mm to 15.5 mm. The gap shows on the wrist and in side photos. Lugs on the genuine watch taper and carry a sharp bevel. Fakes soften that bevel and add metal at the mid case.
Check 2: dial and printing
Applied indices on the genuine dial sit above the surface and catch light on the beveled edges. The printed IWC and SCHAFFHAUSEN text is thin and even under a 10x loupe. Fakes show thick ink, uneven letter spacing, and flat indices glued to the dial.
Look at the subdials. The 30 minute counter sits at 12 and running seconds at 6. Both subdials carry concentric snailing on the genuine dial. A copy uses a flat finish with no texture.
The date window has a sharp frame, the correct font, and no gap between dial and aperture.
Check 3: movement and case back
Calibre 79350 is a Valjoux 7750 base with IWC finishing: Geneva stripes on the bridges, blued screws, and a rotor with engraved IWC branding and the Probus Scafusia mark. Copies show rough milling, a plain rotor, and mismatched screw heads.
Inspect the case back. Engraving should be deep and crisp, with the reference number, case number, and water resistance line in the right order. Photo etched engraving looks shallow and grey. If the watch has a display back, the balance wheel and rotor should be visible and finished.
Serials, paperwork, and price
IWC can confirm a case number. Ask for the warranty card, booklet, and box that match the serial. A watch sold with no papers and a price well under the market is a risk item.
Prices move. Check closed sales on major marketplaces before you agree on a number. No single price proves authenticity. Use price with the physical checks.
Before you buy
- Measure case height with a caliper.
- Photograph the dial at 10x and compare the print and indices.
- Ask for movement photos or inspect the case back.
- Verify the case number with IWC.
- Compare against closed sale prices for the same reference.