Short answer: the ref 5167 is the Patek Philippe Aquanaut, and it is one of the most replicated watches in the world. A good replica nails three things, the embossed dial, the date font, and the case profile. Everything else is detail work. If those three are wrong, nothing else rescues the watch.
What the 5167 actually is
Patek launched the Aquanaut in 1997 as a steel sports watch sitting below the Nautilus. The 5167A-001 is the base model: a 40mm stainless steel case, 8.1mm thick, a tropical composite strap, 120m of water resistance, and the calibre 324 S C inside. That movement runs at 28,800 vph with about a 45 hour power reserve. The thinness matters more than anything when you judge a replica, because plenty of fakes run 1 to 2mm too thick and the whole silhouette changes in the process.
The three tells I check first
Dial texture
The Aquanaut dial is not printed. It is a raised, three dimensional grid, and the squares catch light in different ways as you tilt the watch. Cheap reps print the pattern flat or stamp it too shallow, so it reads like a sticker. On the better versions the ridges have real depth and the recessed squares carry a slight satin grain.
Date font and window
Look at the numerals inside the date window. Patek uses a narrow font with a lot of air around each digit. Replicas often use a fat, generic font, or the window sits too far from the center, or it is set crooked. Tilt the watch under a lamp and check. If the date looks like it came off a wallet calendar, that is the tell.
Case profile
Side on, the 5167 should look close to a coin. The lugs curve down, the bezel is a rounded octagon rather than a circle, and the crown sits inside small guards. Replicas tend to have a flat bezel, thicker lugs, or a crown that pokes past the guards.
Movement: what is inside
Two families dominate. The first is a decorated Japanese automatic, a Miyota 9015 most of the time, with fake bridges and a rotor engraved to look like the 324. The second is a clone of the 324 itself. The Miyota is the safer buy. It keeps time, any watchmaker can service it, and it costs little to replace. The clone looks more convincing through a display back, but the 5167 has a solid caseback, so nobody sees the movement unless the watch is opened. I would take reliability over decoration here every time.
Strap and clasp
The Aquanaut strap is the part that gives most fakes away in person. Genuine tropical rubber has a soft, matte finish and a molded pattern with a slight taper. Replica straps are often shiny, too stiff, or cut with sharp edges. The deployant clasp should be engraved with clean edges, and the Patek cross should sit crisp under a loupe. Sloppy engraving is a fast no.
Bracelet version and other refs
If you want the steel bracelet, that is the 5167/1A, and it is harder to fake well because the links need the right taper and brushed finish. The 5167 also has a rose gold sibling, the 5167R, with a different dial color. Do not mix specs between them when you compare listings.
What to ask a seller
- Exact case thickness in millimeters, measured with calipers, not quoted from a spec sheet.
- Whether the movement is a Miyota 9015 or a clone, and who services it.
- Photos of the date window straight on, no angle.
- Side profile shots with the crown at 3 o'clock.
- Water resistance testing, since gaskets on reps are hit or miss.
Price tiers and expectations
Under about $150 you are looking at a printed dial, a thick case, and a generic movement. The middle tier, about $200 to $400, is where the real competition sits, and that is where dial depth and case profile finally get close. Above that you are paying for movement decoration and small finishing details nobody can see on the wrist. Pay for the outside. That is the only part anyone else sees.