What the 45mm label refers to
Case diameter is measured across the case at the widest point, crown excluded. A 45mm Portugieser is a large watch. On the wrist it reads bigger than a 41mm Portugieser Chronograph, the reference most buyers know. Sellers list 45mm because the number sells. Measure the case with calipers before you trust a listing.
Which genuine models sit at 45mm
IWC's Portugieser range runs from 40mm to 45mm. Two references sit at the top of that range:
- Portugieser Grande Complication, reference IW3774. 45mm case in platinum or red gold. Calibre 79091 with perpetual calendar, minute repeater and chronograph.
- Portugieser Perpetual Calendar Digital Date-Month, reference IW3972. 45mm case in red gold or white gold. Calibre 89801. Two digital discs for date and month.
Other Portugieser models measure 42mm to 44mm. A seller who calls a 42mm Perpetual Calendar a 45mm is describing a different watch. Ask for the reference number the replica copies.
Movement inside a replica
The IW3972 runs calibre 89801 with 68 hours of power reserve. The IW3774 runs calibre 79091. Replicas use Asian automatic movements, most built on the ETA 7750 layout or a 2824 clone. A 7750 clone runs at 28,800 vibrations per hour and gives 40 to 48 hours of reserve. Subdial function varies. On replica perpetual calendars the moon phase and date discs often advance, but the leap year logic does not. The month disc stops on March 1 of the fourth year.
Case, crystal, and finish
- Reports from owners place genuine 45mm Portugieser thickness near 15mm to 16mm. Replica cases run 0.5mm to 1.5mm thicker.
- Genuine uses a domed sapphire crystal with anti-reflective coating on both faces. Many replicas coat one face. Some use mineral glass.
- Gold replicas are steel with gold plating or PVD. Plating wears at the lugs and caseback edges. Weight shows this. A steel 45mm replica on a leather strap weighs about 100g to 130g.
- Genuine water resistance on these references is 3 bar. Replicas print the same number. No replica case is pressure tested at the factory.
What to check in photos
Ask for four images: dial straight on, caseback, crown side profile, and a caliper shot across the case. Check subdial spacing against the genuine layout. On the IW3972 the two date windows sit at 12 o'clock. Check the crown and pusher shape. Check the strap stitch count at the lug ends. A seller who will not send a caliper photo does not have a 45mm case.
Legal note for buyers in the US
Counterfeit watches violate trademark law. Import is a separate matter. US Customs and Border Protection can seize and destroy counterfeit shipments. 18 U.S.C. 2320 covers trafficking in counterfeit goods and carries criminal penalties. Possession alone is not a federal crime. Buying for import or reselling can be.