The short answer
A replica IW371621 is a copy of IWC's 41mm Portugieser Chronograph in stainless steel with a blue dial. The real watch runs an in-house calibre 69355 column-wheel chronograph with a 46-hour power reserve, and no copy has that movement. What good copies do get right is the case profile, the thin bezel, the leaf hands and the twin subdial layout at 12 and 6. Expect to pay $300 to $650 for one worth wearing. Below $250 you are usually buying a watch that misses the case thickness or fakes the chronograph layout.
What the reference actually is
The IW3716 family replaced the long-running 3714 in 2020. Case is 41mm across, roughly 13mm thick, 20mm between the lugs, sapphire on both sides, 30m water resistance, no date. Two subdials: elapsed chronograph minutes at 12, running small seconds at 6. Dial text reads IWC SCHAFFHAUSEN up top and CHRONOGRAPH AUTOMATIC above the 6. Anything on a listing that adds a date window, a third subdial, or a 12-hour counter is not copying this reference, whatever the title says.
What I check first on any copy
- Subdial behaviour. The 6 o'clock subdial should sweep continuously as running seconds. The 12 o'clock subdial should jump in one-minute steps and stop at 30. If the seconds are at 9 o'clock, the maker dropped a stock A7750 in and the dial layout is wrong.
- Case thickness. Most A7750-based copies land at 13.5mm to 14mm. On the wrist that reads chunky next to the genuine 13.1mm. Ask for caliper photos if you care about the profile.
- Dial printing. Look for crisp, evenly spaced letters with no bleeding at the edges. Blue dials in this line are sunburst, so the colour should shift from navy to near-black as you tilt it. Flat matte blue is a tell.
- Hands. Leaf-shaped, faceted, with a clean crease down the centre. Sloppy polishing shows up here under a loupe or a phone macro shot.
- Caseback engraving. The sapphire exhibition back should show a decorated movement with the correct rotor text. Recessed, shallow engraving looks stamped rather than cut.
Movement options you will meet
Three tiers show up in the market. The cheapest uses a generic 7750 with a printed plate, and the pushers feel mushy. Mid tier uses a modified 7750 with the seconds relocated to 6 and better finishing on the bridges. Top tier uses a clone of the 69355 layout with a column wheel feel that is closer to the original, though none of them are the real thing. Ask the seller for a timegrapher reading before shipping. Anything outside plus or minus 15 seconds a day or with a weak amplitude is a pass for me.
Price tiers and what they buy
Under $250: correct silhouette, wrong thickness, thin dial printing, stiff strap. $300 to $450: the sweet spot, with a proper sunburst dial, decent brushing on the lugs, and a relocatable seconds hand at 6. $500 to $650: best dial detail, cleaner caseback work, straps that feel like leather rather than plastic. Beyond that you are paying for scarcity, not quality.
Things that should make you walk
Stock photos with no QC images, a seller who will not show the movement, listings that call it a Portofino or a Portugieser Automatic, and any claim of a genuine IWC movement. Also watch for 42mm or 44mm cases sold under this reference number. The 3716 is 41mm and nothing else.
Setting expectations
A good copy gets you the proportions, the blue dial and the twin-register layout on your wrist for the price of a service on the real one. It will not fool a jeweller with a loupe, and it should not be sold to anyone as genuine. Buy it as a watch you like looking at, keep the bracelet or strap clean, and factor in a service from a local watchmaker within the first couple of years. That is the honest version of this hobby.