Short answer

A fake Audemars Piguet ref 26470 is a counterfeit copy of the Royal Oak Offshore chronograph. The genuine ref 26470 uses a 42 mm steel case, a Mega Tapisserie dial, and calibre 3126/3840. Fakes copy the shape. They fail on case finish, dial print, movement finish, and caseback text. Buying or selling a counterfeit watch is illegal in the US.

What the genuine ref 26470 is

Audemars Piguet introduced the ref 26470 around 2014. It replaced the earlier ref 25721 in the 42 mm Royal Oak Offshore line. The watch has an octagonal bezel with eight hexagonal screws, a chronograph with subdials at 12, 6, and 9 o'clock, and a date window at 3 o'clock. The caseback has a sapphire crystal. The movement is calibre 3126/3840 with a power reserve of about 50 hours. Production ended around 2021.

Case and bezel checks

Genuine cases show sharp bevels. The brushed surfaces run in one direction. The polished chamfers catch light in a thin line. Fake cases show soft edges. The brushing crosses over the chamfers. Bezel screws on genuine watches sit flush. The slots are deep and even. Fake screws sit high or low. The slots look shallow.

Dial and hand checks

The dial has a Mega Tapisserie pattern. On genuine dials the squares are deep and aligned with the markers. Fake patterns look shallow or too wide. The "AUDEMARS PIGUET" print has even letter spacing. Fake print sits high, low, or too thick. The date font is thin. Fake date wheels use thicker numerals. Subdial rings are thin and centered. Fake rings sit off-center. Hands are faceted and polished. Lume fills the markers to a flat surface. Fake lume sits above or below the marker.

Movement and caseback checks

The ref 26470 has a display back. You can see the movement. Genuine calibre 3126/3840 shows fine finishing on the bridges and rotor. Fake movements show rough edges and wrong screws. Caseback engraving on genuine watches is crisp. Fake engraving is shallow and wide. The serial number is unique. Fake serials repeat across batches. A watchmaker can compare the movement to AP service data.

Papers, price, and risk

A genuine ref 26470 sells on the secondary market for tens of thousands of dollars. A "new" watch at a low price is a fake. Ask for service records. Have an AP-trained watchmaker inspect the watch before payment. US Customs and Border Protection seizes counterfeit watches. Trafficking in counterfeit goods is a federal crime under 18 U.S.C. Section 2320. A fake watch has no AP warranty and no service support.