Short answer
IWC does not sell a 39mm Portofino Small Seconds. The number comes from replica listings. It reports the measured case width of the copy. Genuine Portofino models with a small seconds subdial at 6 o'clock measure 37mm or 45mm. A buyer who checks a "39" listing against the IWC catalog will not find a matching reference number.
Genuine Portofino models with small seconds
- Portofino Automatic 37, reference IW4586. Case 37mm. Thickness near 9.4mm. Calibre 35111. Subdial at 6 o'clock.
- Portofino Hand-Wound Eight Days, reference IW5101. Case 45mm. Hand-wound calibre 59210. Eight day power reserve. Small seconds at 6 o'clock.
- Portofino Automatic 40, reference IW3565. Case 40mm. Center seconds. No subdial.
What replica versions use
Most 39mm copies run a Chinese automatic movement. Common calibres are the Seagull ST17 and the Miyota 9015. Some batches use a decorated rotor with IWC engraving copied onto it. Case metal is 316L stainless steel on both the copy and the original. Crystal is sapphire on the better batches and mineral glass on the cheaper ones. Straps are calf leather with an embossed grain, not alligator. Copy prices run from about $250 to $500. A genuine Portofino Automatic 37 lists near $5,900 USD.
Checks that separate a copy from the original
- Subdial placement. Genuine IW4586 sets the subdial 2mm from the dial edge. Copies move it 0.5mm to 1mm.
- Case back engraving. Genuine uses laser etching with even depth. Copies show shallow stamping.
- Movement finish. Genuine calibre 35111 has Geneva stripes and a signed rotor. Copies show painted stripes.
- Serial numbers. Genuine cases carry a reference and a serial on the case back. Copies repeat one number across a whole batch.
Legal status in the US
Trafficking in counterfeit goods is a federal crime under 18 U.S.C. § 2320. A first offense carries up to 10 years in prison. Importing a counterfeit watch by mail is prohibited. U.S. Customs and Border Protection can seize and destroy the shipment under 19 U.S.C. § 1526. Trademark owners can record their marks with CBP and file civil claims under the Lanham Act, 15 U.S.C. § 1114. Personal possession is not a federal crime in most cases. Selling, shipping, and importing is.
What is not known
No replica factory publishes movement specs, case tolerances, or production numbers. Batch quality changes between runs. Two watches from the same seller can differ in crystal, movement, and strap. Any claim of "1:1" or "Swiss made" on a copy of this model has no verifiable basis.