Short answer
The IW371478 belongs to the IWC Portugieser Chronograph line, the 3714 case family. The genuine watch has a stainless steel case 40.9 mm wide and 12.3 mm thick, sapphire crystal front and back, and 30 m water resistance. The movement is Calibre 79350, a Valjoux 7750 base with 31 jewels, 28,800 vibrations per hour, and about 44 hours of power reserve. The dial carries two counters: running seconds at 6 o'clock and chronograph minutes at 12 o'clock. There is no date.
Replicas copy the case, dial, hands, and strap. They do not use an IWC calibre. Buyers compare three tiers: quartz, Asian automatic chronograph, and a higher grade with a cloned 79350 layout. Price runs from about $70 to $600 depending on tier.
IWC lists many 3714 references that differ in dial color, hands, and strap. Confirm the exact IW371478 variant against IWC's own catalog before comparing photos. If a seller cannot name the variant, that is a gap.
Genuine specs to compare against
- Case: stainless steel, 40.9 mm diameter, 12.3 mm thick
- Crystal: sapphire, front and caseback
- Water resistance: 30 m
- Movement: Calibre 79350, automatic, 31 jewels, 28,800 vph, 44 h
- Functions: hours, minutes, small seconds, chronograph with two counters
- Strap width: about 20 mm at the lugs
Replica movement tiers
- Quartz, $70 to $150. The chronograph hand steps once per second. The subdial at 6 o'clock may not run.
- Asian 7750 automatic, $200 to $350. This copies the same base calibre IWC used, so the subdial layout matches. Check rotor noise and chronograph reset.
- Cloned 79350 layout, $400 to $600. Bridges and rotor are decorated to look like the IWC calibre. The finishing is cosmetic.
Ask for a photo of the movement through the caseback. A closed caseback on a reference with a display back is a mismatch.
Case and dial checks
- Dial print. The IWC and Schaffhausen text sits below 12. Letters should be thin. Thick or smeared print points to a low tier.
- Subdial spacing. The two counters must sit on a vertical line with the crown. Offset counters mean the wrong movement.
- Hands. Leaf hands should be flat and polished. Bent or blunt tips show at 3x zoom.
- Caseback engraving. Depth and font weight vary by factory. Compare against a real example, not a stock render.
- Strap or bracelet. Genuine uses alligator leather or a steel bracelet with set end links. Gaps at the lugs are visible.
Magnification above 5x exposes flaws invisible on the wrist. Judge the watch at arm's length if that is how it will be worn.
Buying risks
Counterfeit goods are illegal to import into the United States. US Customs can seize a shipment, and the buyer loses the money. Payment with no chargeback, such as wire or crypto, removes recourse. Sellers who show one watch and ship another are common. Ask for dated photos with a handwritten note.
Maintenance
A 7750 layout is serviceable by most watchmakers. Parts for the Asian version are cheap and available. A service costs $80 to $150 at an independent shop. Gaskets on replicas are often dry, so keep the watch away from water even if the caseback reads 30 m.