Short answer
A replica Patek Philippe Nautilus 6790 is a copy of a Patek Philippe Nautilus. Build quality varies by case finishing, dial print, bracelet taper, and movement. Price does not tell you which parts are correct. No replica matches a genuine Patek Philippe in hand finishing, movement decoration, or resale value.
Is there a Nautilus reference 6790?
Public Patek Philippe catalogs do not list a Nautilus 6790 as a standard steel model. The steel Nautilus line runs from reference 3700 to 5711 to 5811. Numbers in the 6xxx and 7xxx range have covered ladies' models and gem set pieces. Treat any listing that calls 6790 a standard steel Nautilus as unverified. Ask for the case diameter, metal, and movement before you compare replicas.
Benchmarks to compare against
Use known references as yardsticks. The Nautilus 5711/1A measures 40 mm across and 8.3 mm thick. The original 3700/1A measures 42 mm and 7.6 mm thick. A replica that sits 1.5 mm thicker than the genuine case will wear differently on the wrist. Check the bracelet width at the lugs and at the clasp against the genuine spec.
Parts that decide replica quality
- Case: 904L steel on later genuine pieces, 316L on most replicas. Look at bevel width and brushing direction.
- Dial: check the horizontal grooves, the date window bevel, and the print weight of the brand name.
- Hands: lume fill should sit level with the frame. Rough edges show under 10x magnification.
- Bracelet: count links, check clasp engraving depth, and flex each link for play.
- Movement: Miyota 9015, Seiko NH35, and Chinese clones of the 324 S C are common. Ask which one is inside.
- Crystal: single anti-reflective coating on the outside is correct for most Nautilus models. Double coating adds a blue tint.
Checks before you pay
- Ask for photos at 10x of the dial, caseback, and clasp.
- Request a timing reading in six positions.
- Confirm case thickness with calipers, not a photo.
- Ask about water resistance and gasket material. Most replicas fail a pressure test.
- Get the return window in writing.
Legal position in the US
Counterfeit watches are illegal to import and sell in the United States. US Customs and Border Protection can seize shipments under 19 CFR 133. Selling a counterfeit violates the Lanham Act and can bring civil damages. Trafficking carries up to 10 years in prison for a first offense under 18 U.S.C. 2320. Buying for personal use still carries seizure risk.
What a replica cannot do
A replica Nautilus 6790 will not hold value. Genuine Nautilus pieces trade above retail on the secondary market, and Patek Philippe service records follow the case number. A replica has no service history, no maker warranty, and no parts support after the movement fails.