Short answer
The IW371654 sits in the IWC Portugieser Chronograph 41 family. A good replica copies a 41 mm steel case, a vertical subdial layout with the 30 minute counter at 12 and small seconds at 6, a date at 3, and a sapphire display back. The reference is uncommon in the replica market, so not every factory builds it. Confirm the dial color, hands, and strap against IWC's own listing before you buy, because sellers reuse the number for several builds.
What the reference is
Portugieser Chronograph 41. Stainless steel case, 41.0 mm wide, 13.0 mm thick, 20 mm lugs. Sapphire crystal front and back. Crown at 3, pushers at 2 and 4. Movement is the IWC calibre 69355, an automatic column wheel chronograph, 28,800 vph, 46 hour power reserve. Water resistance is 30 m. Dial has applied numerals, feuille hands, a 30 minute counter at 12, small seconds at 6, and a date aperture at 3.
What replicas match
- Case size and lug width. Most copies measure 41 mm with 20 mm lugs.
- Subdial positions. The 12/6 layout fits a modified 7750 base, so vertical spacing stays close.
- Crystal and display back. Sapphire on both sides with an engraved rotor is standard from the mid tier up.
- Dial furniture. Applied numerals, printed track, and feuille hands appear on high grade copies.
Where replicas differ
- Thickness. An Asia 7750 based chronograph adds bulk. The original measures 13.0 mm. A copy at 14.5 mm or more sits higher on the wrist.
- Movement finish. The 69355 has Geneva stripes, a skeletonized rotor, and engraved bridges. Copy decoration is printed or shallow.
- Power reserve. Original is 46 hours. A 7750 copy runs about 40 hours and loses rate as it unwinds.
- Date wheel. Font weight and window bevel are the two common tells.
- Engraving depth. Caseback text on the original is shallow and crisp. Deep stamping points to a cheaper case.
Checks before you pay
- Ask for a photo of the caseback and of the movement through the display back.
- Ask for case thickness measured with calipers, in millimeters.
- Ask for a timegrapher reading. Minus 10 to plus 15 seconds a day is a normal range for these movements.
- Confirm the strap or bracelet option. Leather, rubber, and steel all appear under the same number in the replica market.
- Get the return policy in writing. Movement faults show up inside the first two weeks.
Price tiers
Three tiers exist. Entry copies run $150 to $250 with a generic 7750 and low grade sapphire. Mid tier runs $250 to $400 with a better case, sapphire on both sides, and a decorated rotor. Top tier runs $400 to $600 with a closer case profile, correct hand shape, and a serviced movement. Paying more than $600 for this reference buys little extra.
What is not known
No single factory build has been verified as a match for IW371654. Seller photos under this number show different dial colors and strap types. Treat the number as a starting point and judge the watch in front of you. IWC lists the official case, dial, and strap combination for the reference. Compare against that page, not against seller text.