Short answer
The replica IW371740 is a copy of the IWC Portugieser Chronograph Classic, a 42mm stainless steel chronograph with two subdials, a date at 3 o'clock, and a dial that lives or dies on how thin the printed numerals are. Good versions get the case shape, crystal dome, and strap right. Almost all of them get the chronograph movement wrong in some way, and that is where your money either holds up or falls apart.
If you want a number: expect the case, dial, and hands to be convincing at arm's length on any decent replica. Expect the pusher feel and the caseback engraving to be the tells that give it away to anyone who has handled the real thing.
The genuine reference, briefly
IWC's Portugieser Chronograph Classic runs a 42mm case, sapphire front and back, and the in-house calibre 89361 with roughly a 68-hour power reserve. The layout is what makes it recognizable: a combined hour and minute counter at 12, running seconds at 6, and a date window at 3. Arabic numerals, leaf-shaped hands, and a rail-style minute track around the outer edge.
That layout is also the hardest part to copy well, because the two subdials have to sit at the correct distance from center and the printing has to stay crisp at 42mm.
Movement: the real dividing line
Replicas of this reference generally fall into three buckets.
- Quartz. Cheap, correct-looking at a glance, and the chronograph usually works as a simple start-stop-reset with no smooth sweep. Sweeping seconds are wrong.
- Asian automatic chronograph modules. Often a 7750-derived movement with a modified layout. The pusher feel is heavy and the rotor is loud. Subdial positions are sometimes a millimeter or two off.
- Decorated clones. Movement plates engraved and finished to mimic the IWC calibre, and the ones people pay the most for. Hand-winding feel and chronograph reset are the giveaway.
If you care about the chronograph working smoothly, the 7750-based route is the safer bet. If you mostly care how it looks through a display back, the decorated version wins.
Dial and case details worth checking
I look at four things before anything else.
- Numeral thickness. Genuine Portugieser numerals are applied and slightly raised. Replicas often print them flat, and the difference shows in raking light.
- Subdial spacing. The gap between the 12 and 6 subdials should look balanced, not crowded toward the center.
- Crystal dome. This reference has a noticeably domed sapphire. Flat crystals make the whole watch look cheap.
- Case flanks. The lugs curve down and the case sides should be polished to a mirror, with brushed surfaces only where the original has them.
Strap quality matters more than most people expect. A flimsy alligator-pattern strap ruins an otherwise solid replica, and swapping it for a decent leather strap is the single cheapest improvement you can make.
What replicas still get wrong
The caseback engraving is usually too shallow, the reference number format is sometimes off, and the crown threads feel gritty. Water resistance claims are meaningless on a replica; treat any rating as decorative and keep it away from water.
Servicing is the other issue. An authorized IWC service center will not touch a counterfeit, so any repair goes to an independent watchmaker who works on clone movements. Factor that into the price you are willing to pay.
Who this suits
This is a dressy chronograph, not a sports watch. It works with a suit, a button-down, or a plain tee, and it wears larger than 42mm suggests because the dial is almost all open space. If you have a wrist under about 6.5 inches, try to see one in person first.
Buy the version whose movement you understand, not the one with the longest spec sheet. On this reference, movement honesty beats marketing every time.