Short answer
A listing named replica Portofino Automatic 42 copies an IWC Portofino with a 42 mm case. IWC itself does not sell a Portofino Automatic at 42 mm. The Portofino Automatic comes in 40 mm (ref IW3565, calibre 35111) and 37 mm (ref IW4586). The 42 mm Portofino is the Chronograph, ref IW3910, with calibre 79320, two subdials, and a day-date window at 3. Replica sellers mix the two names. Check the dial: a 42 mm case with three hands and a plain date at 3 matches no IWC catalog page.
Genuine specs to compare
Portofino Automatic 40 (IW356501)
- Case: stainless steel, 40 mm wide, 9.2 mm thick
- Movement: IWC calibre 35111, 25 jewels, 28,800 vph, 42-hour power reserve
- Crystal: sapphire, front and caseback
- Water resistance: 3 bar
- Dial: Roman numerals at 12 and 6, date at 3, no subdials
- Lug width: 20 mm
Portofino Chronograph 42 (IW3910)
- Case: stainless steel, 42 mm wide, 13.5 mm thick
- Movement: IWC calibre 79320, Valjoux 7750 base, 25 jewels, 28,800 vph, 44-hour power reserve
- Dial: subdials at 12 and 6, day-date at 3, two pushers
- Water resistance: 3 bar
Replica tiers
Three tiers hold the market. Entry builds run $150 to $300 with a 316L steel case, mineral glass or low-grade sapphire, and a 21-jewel Chinese automatic. Mid tier runs $300 to $600 and adds a Seagull ST2130 or Miyota 9015, real sapphire, and an anti-reflective coating. Top tier runs $600 to $1,200 and uses an ETA 2892-A2 or Sellita SW300-1, with closer dial printing and case finishing.
Case thickness is the first tell. The 40 mm automatic measures 9.2 mm. A replica at 12 mm or more sits high on the wrist and will not fit under a shirt cuff. Weight is the second tell. Steel cases at 40 mm land near 65 g to 75 g without a strap.
Checks before buying
- Measure the case with calipers. Diameter, thickness, lug width.
- Compare the date font and window position to a photo of the genuine reference.
- Count the crowns and pushers. One crown means automatic, three means chronograph.
- Ask for photos of the caseback and the movement, not stock images.
- Confirm lug width at 20 mm for both references.
- Ignore water-resistance claims. Gaskets in replicas are not pressure tested.
Service cost matters. A Swiss ETA or Sellita movement can be serviced at a local watchmaker for $150 to $300. Chinese movements are replaced, not repaired, and parts can be hard to source.
Legal status
Replica IWC watches are counterfeit goods. US trademark law, 15 U.S.C. 1114, covers the name and the logo. US Customs and Border Protection seizes counterfeit shipments under 19 U.S.C. 1526. Resale brings fines and possible criminal charges. IWC service centers will not touch the watch, and many independent watchmakers refuse the work.