Answer first
IW938720 does not appear in IWC's public reference list. IWC uses the format IW plus six digits, such as IW503401 and IW377709. A listing that carries IW938720 is a seller label. Judge the watch on the case, dial, and movement. Do not judge it on the number alone.
How IWC reference numbers work
Each IWC reference points to one case, dial, and movement combination. The number sits on the caseback and on the warranty card. IW938720 fits the digit pattern, but I cannot confirm a matching IWC model. Ask the seller for a photo of the caseback engraving. Compare it with the reference printed on the card. A mismatch is a warning sign.
Checks before you buy
- Case diameter. Measure the real case, not the listing photo.
- Movement. Note the caliber, beat rate, and power reserve.
- Dial print. Look at font weight, spacing, and the logo.
- Caseback. Compare engraving depth and letter style.
- Water resistance. Most replicas fail a pressure test.
Movement and finish
Replica sellers pair a case with a movement from a third party. Common options are the Seiko NH35, the Miyota 9015, and Chinese clones of the ETA 2824. Beat rates differ: 21,600 vibrations per hour for the NH35, 28,800 for the Miyota and the ETA clone. Ask for the caliber name. A seller who cannot name the movement cannot support a service claim.
Price and red flags
Price tracks the movement and the case finish. A watch with a Japanese automatic movement costs more than one with a quartz module. Red flags: no caseback photo, no movement photo, no return window, and a claim of 1:1 with no measurements. Water resistance claims above 100 m need a test report.
Questions for the seller
- What is the case diameter in millimeters?
- What caliber is inside?
- Does the listing include a caseback photo?
- What is the return period?
If the seller cannot answer these four items, stop. The reference number will not help you.