Short answer
"Portofino 39" means an IWC Portofino with a 39 mm case. The name appears in replica listings that copy those cases. Genuine Portofino watches have been sold at 37 mm, 39 mm and 40 mm, so the number alone tells you little. The reference number tells you more. Ask for it first, then check case size, lug width, dial print and movement.
Genuine specs to compare against
- Case: 39 mm steel or gold, measured across the case at 3 and 9 o'clock, crown left out of the count.
- Lug width: 20 mm on 39 mm Portofino cases.
- Case thickness: about 9.5 mm to 11.5 mm, model dependent.
- Automatic movement: IWC calibre 35111, Sellita SW300 base, 25 jewels, 42 hour power reserve, 28,800 vibrations per hour.
- Chronograph movement: IWC calibre 79350, Valjoux 7750 base, 44 hour reserve.
- Crystal: sapphire with antireflective coating on both faces on most references.
- Water resistance: 30 m to 50 m on the dress references.
Replica tiers and the movements inside
Listings fall into three price bands: about $100 to $250, about $300 to $550, and about $600 to $900. Price does not prove quality. Ask what the watch runs on.
- Miyota 9015: 24 jewels, 28,800 vph, 42 hour reserve. Japanese, common in mid tier builds.
- Seagull ST2130: ETA 2824 layout, 28,800 vph. Chinese, found in mid and upper tiers.
- Decorated movements: plates and rotors etched with the calibre number of the genuine watch. The font and the finish rarely match the real part.
- Quartz: found in the cheapest builds. The seconds hand ticks once per second.
Checks that matter
- Measure the case with calipers. 39 mm, not 40 mm, not 38 mm.
- Measure the gap between the lugs. 20 mm.
- Look at the indices. Applied metal on the genuine dial. Printed or glued on low tiers.
- Compare the date numerals to IWC catalog photos at the same magnification. Font and weight differ on copies.
- Tilt the watch under a lamp. Sapphire with coating shows a faint blue or violet tint. Mineral glass shows none.
- Read the caseback. Reference format, engraving depth and letter spacing.
- Request a photo of the rotor, the balance wheel and the crown side of the movement.
Photos to request from a seller
Ask for a straight-on dial shot, a side profile, a caseback shot and a movement shot with the caseback removed. Add one photo of the watch next to a ruler. Skip sellers who send stock images only.
Limits of photo checks
A photo cannot confirm case alloy, gasket condition or water resistance. Replica watches are not pressure tested by the makers, so do not swim with one. Service parts for clone movements are not sold by the original brands, so a repair can take weeks or fail outright.