Short answer
IW371628 is an IWC reference number in the Portugieser Chronograph family. The 3716 line uses a 41 mm steel case, 13.1 mm thick, 20 mm lugs, no date window, and two subdials. The small seconds sits at 6 o'clock. The 30-minute chronograph counter sits at 12. The movement is IWC calibre 69355, an automatic column wheel chronograph with a 46-hour power reserve. Replica versions sell for about $350 to $650 and run on Asian 7750-type movements or quartz. The caseback and the movement are the two parts that fail a close check.
What the reference number covers
IWC packs case metal, dial color, hand finish, and strap into the digits after 3716. One watch head ships in several combinations. IWC lists current variants on its own site and through authorized dealers. This guide could not confirm which dial, hands, and strap the suffix 28 maps to. Confirm the combination with IWC or an authorized dealer before you compare a copy to a photo.
Genuine specs to compare
- Case: 41 mm diameter, 13.1 mm thick, stainless steel, 20 mm lug width
- Movement: calibre 69355, automatic, column wheel, 4 Hz, 46-hour reserve
- Dial: applied numerals and indices, leaf hands, no date
- Crystal: domed sapphire, antireflective coating on the inner face
- Water resistance: 3 bar (30 m)
- Strap: alligator leather on a steel pin buckle for most variants
Where replicas diverge
Subdial layout. A stock Asian 7750 puts running seconds at 9 o'clock and a 12-hour counter at 6. A copy that shows the wrong function in either subdial is easy to spot at arm's length.
Case height. Copies of the 3716 measure 14 mm to 15.5 mm at the crystal. The crystal dome accounts for most of the gap.
Crown and pushers. The genuine crown carries the IWC fish logo and a defined knurl. Copy crowns are flat and shallow. Copy pushers feel loose at the start of travel.
Dial print. Look at the weight of "IWC" and "SCHAFFHAUSEN". Copy printing is thinner, and the subdial rings sit at the wrong radius.
Caseback. The 3716 uses a display back on most variants, which puts the rotor, bridges, and engraving in view. Copy rotor engraving is shallow and the perlage is coarse.
Hands. Genuine leaf hands are polished on the top facet and drawn on the sides. Copies show one flat finish.
Movement types found in copies
- Asian 7750 with a reworked seconds and chronograph arrangement. Winding is unidirectional on some builds. Start and stop feel heavy.
- Seiko VK64 meca-quartz. The chronograph hand snaps to zero. No balance wheel is visible through a display back, so the watch fails a visual check.
- Quartz with faux subdials. The subdial hands do not move at all.
Price range and legal status in the US
Replica prices for this reference run $350 to $650 from the factories that market it. Listings under $150 are quartz or carry faux subdials. In the US, trafficking in counterfeit goods falls under 18 U.S.C. 2320. CBP can seize counterfeit shipments at the border, including a single watch sent to a private address. Selling a replica as a genuine IWC is a separate offense.
Checklist before you pay
- Ask for case thickness measured with calipers in the photo
- Ask for a video of chronograph start, stop, and reset
- Ask which subdial holds the running seconds
- Ask for a caseback photo with the movement visible
- Ask for the lug width and confirm 20 mm
What this guide cannot confirm
The exact dial and strap combination for IW371628. Reference suffixes change with regional and boutique editions, and some references drop out of the catalog. Treat a listing that shows one photo for several references as unverified.