The short answer: treat IW371648 as a specification to verify, not a badge to trust. The reference belongs to the IWC Portugieser Chronograph IW3716 family, so every useful decision comes from comparing a specific watch against that family's known dimensions, namely a 41 mm steel case, 20 mm lugs, a two counter layout, and the in-house calibre 69355. Two facts should shape the purchase before you look at a single photo. Counterfeit watches are illegal to sell and illegal to import into the United States, and no replica carries the real movement. If resale value, serviceability, or long term ownership matter to you, the honest answer is the genuine watch or nothing.

What the IW371648 reference actually is

The reference sits inside the Portugieser Chronograph family, a line defined by a large clean dial and a two counter chronograph layout. Shared traits across the family include a 41 mm stainless steel case, roughly 13 mm of thickness, a 20 mm lug width, sapphire crystal front and back, applied Arabic numerals, leaf shaped hands, small seconds at 6 o'clock, a 30 minute chronograph counter at 12 o'clock, and water resistance rated to 3 bar. The current generation runs the in-house calibre 69355, a column wheel chronograph with about 46 hours of power reserve at 28,800 vibrations per hour.

Because references in this family differ mostly by dial colour, finish, and strap, confirm the exact dial and case configuration of IW371648 against official documentation before you compare anything. A seller who cannot state those details is not describing a specific watch. They are describing a photograph.

What to check before you commit

  • Subdial honesty. The counter at 12 must count elapsed minutes and the one at 6 must run as a true small seconds. Faux subdials, a 24 hour indicator, or a seconds hand that stutters are immediate disqualifiers.
  • Dial printing and numerals. Applied numerals should be faceted and polished, sitting proud of the dial with crisp edges. Printing should stay sharp under a loupe rather than feathering at the edges.
  • Hand finish. The leaf hands should be flat, evenly polished, and long enough to reach the minute track.
  • Chronograph feel. Start, stop, and reset should each feel distinct. A mushy pusher or a reset hand that lands off zero signals a cheap movement module.
  • Case and caseback. Check engraving depth, crystal clarity, and whether the display back shows a finished movement or a printed plate.
  • The actual unit. Ask for a live video with the chronograph running and the caseback shown, filmed that day, with a handwritten note placed beside the watch.

Parameter bands worth memorising

  • Case diameter: 41 mm, allow a small tolerance of roughly 0.3 mm
  • Case thickness: about 13 mm
  • Lug width: 20 mm
  • Water resistance: 3 bar, which means splash resistance and nothing more
  • Movement rate: 28,800 vibrations per hour, or 4 Hz
  • Power reserve: about 46 hours on the genuine calibre 69355
  • Chronograph layout: 30 minute counter at 12, small seconds at 6

Any listing that contradicts these numbers is describing a different watch, and you should price and judge it on that basis rather than on the reference number in the title.

Pitfalls that cost buyers the most

Customs risk comes first. Counterfeit goods are subject to seizure and destruction at the US border, and a seized parcel usually means you lose both the watch and the money with no route to a refund. Legal risk follows. Trafficking in counterfeit goods is a federal offence, and buying stock with intent to resell carries real exposure. After that come the ordinary failures: stock photos lifted from another seller, movement substitutions where a decorated third party calibre stands in for the in-house movement, payment methods with no chargeback rights, and the servicing dead end. Independent watchmakers often refuse counterfeit movements, and replacement parts do not exist in any supply chain you can access.

FAQ

Does the replica use the same movement as the genuine watch?

No. Calibre 69355 is made in house by IWC. Copies rely on modified third party mechanical movements or quartz, which is why the chronograph feel and the subdial behaviour give them away quickly.

Can a jeweller or watchmaker tell it apart?

Usually yes, and often within a minute. Dial printing, hand finish, caseback engraving, and the movement behind the display back are the four fastest tells.

Will a replica hold its value?

No. Counterfeit watches have no collector market, no service history, and no resale channel beyond the same grey market that sold it to you.

Is it legal to buy one?

Importing counterfeit goods into the United States is prohibited and shipments are subject to seizure. Selling them is a federal crime. Treat any offer that skips past those facts as a warning about the seller.