Short answer
The Portofino Midsize 39 is a 39 mm IWC case. A replica of it stands on three numbers: case diameter 39.0 mm, case thickness near 9.4 mm, and lug width 20 mm. Ask for caliper photos that show the crown side and the caseback in one frame. A seller who cannot send them is reselling stock photos.
What the genuine reference is
IWC builds the Portofino Automatic 39 in stainless steel with a sapphire crystal, a date window at 3 o'clock, and applied hour markers. Water resistance is 5 bar. The movement is IWC calibre 32110. Retail sits near $6,000 depending on the dial and strap variant. Confirm the case and movement numbers on IWC's page for the exact reference before you compare a replica.
Measurements to demand
- Case diameter: 39.0 mm. A 40 mm case is a different Portofino reference.
- Thickness: 9.2 to 9.6 mm on replicas that copy the case profile. Anything over 11 mm hides a thick movement or a spacer ring.
- Lug width: 20 mm.
- Weight: 55 to 70 g for the head on a leather strap.
Movement tiers
Three builds show up in listings. A quartz build costs $100 to $180 and has a ticking seconds hand, which no Portofino has. A Miyota 9015 build costs $250 to $400 and runs at 28,800 vph. A build with a decorated Asian or Swiss automatic costs $450 to $700 and should show a rotor and bridges that match photos of calibre 32110. Ask for a timegrapher photo. Rate, amplitude, and beat error are numbers a seller can produce in one minute.
Dial, hands, and printing
Check the date window. It should sit centered under the 3 o'clock index with even gaps on both sides. Look at the applied markers from the side. Glue squeeze-out and uneven height show up in macro photos. The seconds hand should reach the chapter ring hash marks. Dial print should read level at 10x magnification.
Case, crystal, and caseback
Case flanks should be brushed with polished bevels. A fully polished case is a different reference. The sapphire crystal should show no blue tint at an angle. Caseback engraving depth matters. Shallow laser etching on a plain steel back points to a low tier build.
Strap and buckle
Genuine Portofino straps use alligator with a signed pin buckle or a deployant clasp. Replica straps range from synthetic leather to calf. Add $30 to $80 for a replacement strap, because the strap in the box is the weakest part of most kits.
Red flags
- No caliper photo.
- One photo reused from an IWC press image.
- Claims of "1:1 Swiss made" with no movement name.
- Price under $100 for an automatic.