The short answer
The IW371620 is a 41 mm stainless steel IWC Portugieser Chronograph, and the replica market treats it as a mid-tier build rather than a headline Super Clone. Solid versions exist at $280 to $600. None of them are the watch they copy. The gap between a cheap rep and a good one comes down to the movement and the dial printing, not the case shape, because the case is the easy part to machine.
What the real one is
Reference IW371620 sits in the modern Portugieser Chronograph family. Steel case, 41 mm across, around 13 mm thick, 20 mm lugs, sapphire front and back, and IWC's in-house 69355 chronograph movement with roughly 46 hours of power reserve at 4 Hz. Two registers, one at 12 for elapsed minutes and one at 6 for running seconds. Leaf hands, applied numerals, and a dial that is mostly empty space. That emptiness is why fakes of this reference are so easy to spot when the printing is off.
Movement is the whole conversation
Most reps of this reference run an Asian 7750 derivative. It works, it winds, the chrono resets, and it is also 2 to 3 mm thicker than the genuine 69355, which pushes the case out to about 15 mm. A few higher-tier builds use a decorated clone with a column-wheel look and a display caseback rotor engraved like the real thing.
What I look for:
- Second hand at 6 should sweep smooth, not stutter. Anything under 6 beats per second is a tell you can see from a foot away.
- Chrono start should feel crisp with no mush. Pushers on cheap reps travel too far.
- Reset must snap back to zero every time, not drift a second or two.
- Rotor noise. Listen from 6 inches. A rattling rotor is a $100 movement in a $400 case.
Dial and case tells
The numerals should be applied, not printed, and they should catch light at the same angle as the hands. On budget reps the numerals sit flat and the edges look rounded under a loupe. Subdial rings are often too thick, and the hash marks get crowded near the center.
Case finishing matters less than people expect. Brushed flanks and polished chamfers are standard now. What gives away a rep is the crown: the IWC logo stamp is usually shallow or slightly off-center, and the crown action feels gritty when you set the time.
What pricing actually buys
Under $200 gets you a 7750 in a generic case with printed markers. Around $250 to $350 gets applied numerals and a decent bracelet or strap. Above $500 you are paying for a decorated movement, better crystal with real anti-reflective coating, and a clasp that does not feel like folded tin. Beyond $700 for this reference, you are mostly paying for a story.
How I would check one before paying
- Ask for a video of the chrono running and resetting, with sound on.
- Check the thickness with calipers if the seller will do it. Over 14.5 mm is a hard pass for me.
- Compare the dial photo against official IWC photography for the exact variant you are ordering, side by side, same zoom.
- Confirm the subdial at 12 counts minutes, not hours.
- Ask about water resistance claims, then assume zero and keep it away from water.
Bottom line
The IW371620 does not need a perfect replica to look convincing on a wrist, because the design is quiet. It needs a smooth-running movement, applied numerals, and a thickness that does not betray it. Get those three and you have a watch that wears like the real thing from across a table. Skip them and no amount of case polishing will help.