Quick answer
A replica Luminor Due 3 Days is a Panerai-style automatic built around the slim Luminor Due case and the locking crown bridge of the original. The "3 Days" label refers to the 72-hour power reserve of the genuine P.900 calibre. Most replicas will not hold that reserve, so the purchase decision comes down to three things: case thickness, dial detail, and whether the movement you receive can run near three days on one full wind. Verify all three before you send money.
What you are comparing against
The genuine Luminor Due 3 Days Automatic uses the Panerai P.900 calibre, a 4.2 mm thick automatic rated at 72 hours. Case sizes run from 38 mm to 45 mm, and the 42 mm automatic references measure about 10.5 mm thick. That thickness number matters more than any other spec. A case that arrives at 13 mm or more is a Luminor Marina body wearing a Due dial, and it will sit on the wrist like a different watch.
Before you order
- Know your wrist circumference in millimeters and the case diameter you want: 38, 42, or 45 mm.
- Choose a reference number first, for example a 42 mm automatic with small seconds at 9 and a date at 3.
- Ask the seller for the movement name, case thickness in mm, and lug width in mm.
- Get the return window and the payment terms in writing before checkout.
How to evaluate a replica Luminor Due 3 Days
- Measure case thickness with calipers when the watch arrives. A 42 mm Due should read between 10.5 mm and 11.5 mm.
- Wind the crown 40 full turns, set the time against a known clock, and leave the watch in a drawer.
- Write down the time reading at 24, 48, and 72 hours. Any stop before 60 hours means the reserve claim is marketing copy.
- Work the crown bridge lever. It should lock with light finger pressure and hold the crown flat against the case with no side play.
- Inspect the sandwich dial under a desk lamp. The cutout edges should be clean, the lume level, and the printed text straight against the index line.
- Study the date window at 3 o'clock. Expect a thin font, a square cut, and a numeral centered in the aperture.
- Turn the watch over and read the caseback engraving. Letters should be crisp, and the reference number should match the model you ordered.
- Angle the dial at 45 degrees to check crystal dome and anti-reflective tint. Heavy blue reflection is a common giveaway.
- Flex the strap at the lugs and close the buckle. Leather should fold with some give rather than crack at the bend.
- Skip the sink test. Unless the seller lists a gasket rating, treat water resistance as unproven and keep the watch dry.
Movement notes
Many replicas in this range use an A7750-derived automatic with a decorative plate. Those movements run about 40 hours on a full wind and drift more than the listing suggests. Others use a Seagull ST25 or a modified ETA clone that can reach 60 to 70 hours. Winding feel tells you something as well. A gritty or springy crown often points to dry seals or a roughly finished stem, and that shows up as timekeeping error within the first month.
Legal and practical note
Counterfeit watches that carry a trademarked name are illegal to import into the United States, and shipments can be seized by Customs and Border Protection. Seller quality in this market varies. Keep order records, pay with a method that offers a dispute process, and budget for a service if the watch runs outside plus or minus 20 seconds a day.
Care after arrival
Store the watch on a soft cloth, not on a hard surface, and keep it away from magnets such as laptop lids and speaker cabinets. Have a watchmaker check gaskets and regulation once a year if you wear it often. A new strap every 12 to 18 months keeps the look sharp, and a 24 mm or 22 mm replacement is easy to source for most Due references.