Short answer: a replica IW371619 is a counterfeit of the IWC Portuguese Chronograph in the IW3716 family. The better copies get the 40.9 mm case and the twin subdials right, then fail on thickness, movement, and dial printing. The weak copies fail on all four. No copy matches the in-house caliber 69355, so any example gives itself away once you measure it or look at the back.
This guide covers the checks that separate the closer copies from the obvious ones, plus the legal reality of owning and reselling one in the United States.
What the IW371619 Is
The reference sits in the Portuguese Chronograph line, a two-register chronograph with no date window. The genuine watch uses a 40.9 mm stainless steel case at about 13 mm thick, sapphire on both sides, and caliber 69355 with a column wheel and vertical clutch. Every replica has to fake those numbers, and most fall short on the last one.
Checks in Order
- Measure the case across the bezel at 3 and 9 o'clock. The genuine figure is 40.9 mm. Copies often land between 41.5 mm and 42.5 mm.
- Measure thickness with a caliper at the center of the caseback. Genuine is roughly 13 mm. Anything at 14 mm or more carries a 7750-style movement underneath.
- Look at the subdials. They sit at 12 and 6. Confirm the hands are centered in each register and the outer track stays crisp at 10x magnification.
- Read the dial printing. The IWC wordmark and SCHAFFHAUSEN should be sharp, level, and spaced with correct kerning. Fuzzy edges or a font that reads wide point to a reprint.
- Check the applied numerals and hands. Genuine indices are polished and sit flush. Replica indices sit high or show glue at the base.
- Inspect the caseback engraving. Look at the depth and the letterform of the reference number. Laser etching on copies is shallow and grey next to stamped genuine metal.
- Wind the watch and listen. A 7750-based copy has a gritty winding feel and a rotor that rattles when you tilt the case. Caliber 69355 winds smooth and the rotor stays quiet.
- Press the chronograph pushers. Genuine vertical clutch action is light and the seconds hand starts with no jump. Copies running a horizontal clutch make the hand stutter at start.
- Time the reset. Push the lower pusher and watch the hand snap back to 12. A slow or bouncing return means the chronograph module is worn or low grade.
- Check the strap and buckle. Genuine alligator has tight, irregular scale patterns. Replica straps use embossed calf with uniform scales. The tang buckle should be signed and the spring bars should seat with no play.
Red Flags That End the Conversation
- A seller claiming an in-house movement at a price far under market.
- Photos that hide the caseback or the side profile.
- A serial number that does not match the reference on the caseback.
- Boxes and papers with wrong fonts or a certificate carrying no dealer stamp.
Where the Money Goes
Two tiers dominate the market. The first uses an Asian 7750 with a decorated rotor and sells for a few hundred dollars. It keeps time, but the case is thick, the pushers feel stiff, and the dial printing never matches. The second tier uses a modified clone movement, thinner cases, and better dial work. It costs several times more and still has no service network, no parts supply, and no resale path.
Legal and Practical Reality
Selling a counterfeit watch is trademark infringement in the United States, and an imported copy can be seized and destroyed at the border. Buying one for personal use is not a criminal act in most US jurisdictions, but the watch has no resale value on any legitimate platform, no warranty, and no service path. Parts come from the same gray supply chain as the watch, so a repair often costs more than the copy did.
If the goal is the look of the Portuguese Chronograph on a budget, a homage with a legitimate brand on the dial carries none of those problems. If the goal is the genuine article, buy from a dealer with a documented service history and verify the reference against IWC's published data before you send money.