The replica IW371618 is a copy of the 41 mm IWC Portugieser Chronograph, and a good one gets four things right: the case profile and thickness, the dial proportions with the 30-minute counter at 12 and small seconds at 6, the column-wheel chronograph feel at the pushers, and clean, thin printing. Those four checks separate a wearable copy from a shelf piece, and all of them can be verified in about five minutes.
What are the key specs of the IW371618?
The genuine watch uses a stainless steel case of roughly 41 mm across and about 13 mm thick, with a 20 mm lug width and a domed sapphire crystal. Inside sits the in-house calibre 69355, a column-wheel chronograph with a vertical clutch and about 46 hours of power reserve. Water resistance is rated at 3 bar, which means splash resistance rather than swimming.
Leaf-shaped hands, applied Arabic numerals, and a slim feuille-style chronograph hand define the front. A replica that misses any of these proportions reads wrong on the wrist even in photos.
How do you check the case and crystal?
Measure the case with calipers, not with your eyes. Thin-case copies run 12.5 to 13.5 mm; thicker ones hit 15 mm and sit high on the wrist.
- Lug tips should curve down and finish sharp but not knife-edged.
- The crystal should have a gentle dome and show no rainbow halo under a lamp.
- Crown and pushers sit flush, with no gap at the case band.
- Case back engraving is shallow and crisp, not sandblasted and blurry.
Which dial details give a replica away?
Printing is the fastest tell. Genuine IWC text is fine, evenly spaced, and sits under a lacquered or sunburst finish that changes tone as the light moves.
- Look at the sub-dial spacing. The distance between the 12 and 6 counters should match the genuine reference.
- Check numeral thickness. Pale, fat, or gold-tone numerals on a steel reference are a fail.
- Inspect the chapter ring. Minute ticks must be sharp and evenly spaced all the way around.
- Turn the watch over in your hand. Flat, dull dials usually mean printed indices instead of applied.
How does the movement feel?
Most copies run a modified Asian 7750 with an added chronograph module to move the counters to 12 and 6. That setup works, but the pushers feel soft and the reset snap is muted compared with a true column wheel.
Press start, stop, and reset in sequence and listen. A clean click with an instant flyback to zero is a good sign. Grinding or a hand that drifts off zero is not, and a service will cost more than the watch.
What should you pay and how should you care for it?
Expect the better 1:1 grade to sit in the low-to-mid hundreds of dollars, with cheap versions well below that. Anything above that range buys diminishing returns rather than a better watch.
Keep the chronograph running occasionally to move the lubricants, avoid pressing reset while the chrono is running, and keep the watch away from water regardless of the case back rating. A soft cloth and a dry brush around the lugs covers most of the cleaning.