To spot a fake Audemars Piguet ref 26470, start with the movement, because that is where replicas fail hardest. A genuine Royal Oak Offshore 26470 runs AP calibre 3126/3840, a modular chronograph built on the calibre 3120 base, with 59 jewels, roughly 365 components and a gold winding rotor. Then work through five checks in this order: the eight bezel screws, the case and bracelet finishing, the Mega Tapisserie dial, the caseback engraving and serials, and the paperwork. The first two take a minute and screen out most fakes. The last two need a loupe, a light and a watchmaker.

Check 1: The eight bezel screws

The Royal Oak bezel is held by eight hexagonal screws that are machined and functional, not decorative. On genuine watches they sit flush in their countersinks, the hexagon walls are crisp and the metal has a clean polished edge.

• What you want to see: perfectly formed hexagons, even depth on all eight, no burrs, no tool marks around the heads, and slight but consistent polishing.
• What gives a fake away: over-polished or rounded hexagons, screws that sit proud or recessed at different heights, slots cut at random depths, or heads that look cast rather than cut.

This single check eliminates a large share of counterfeits, including some high-tier ones, because the screws are machined in low volume and are expensive to copy.

Check 2: Case, bracelet and finishing

Genuine Offshore cases combine satin brushing on the flat surfaces with mirror-polished bevels, and the two meet on a sharp, straight line. Run a fingernail along the chamfer. On the real watch it catches cleanly and the width of the bevel stays constant.

• Genuine: crisp edge transitions, uniform brushing direction, polished bevels with no softness, tight tolerances at the bezel and caseback.
• Fake: rounded or wavy chamfers, brushing that runs in different directions, gaps at the bezel, and a case that often measures thicker than the reference because a third-party movement needs more room.

Also check the pushers and crown for play. Genuine chronograph pushers travel smoothly and return with a clean click. Fakes often feel gritty or stick halfway.

Check 3: The dial

The Mega Tapisserie dial is a grid of small pyramids stamped into the surface. Under magnification the peaks should be sharp and even, with a matte finish between them.

• Dial tells: uneven pyramid height, a glossy or plasticky surface, fuzzy or double-struck printing, a date font that is too bold or too narrow, and subdial rings that sit flat instead of in a recessed well.
• Hands and lume: genuine hands have faceted sides with polished bevels and a flat top, and the lume fill is level and even. Painted or lumpy lume is a red flag.

Subdial layout is also worth confirming: the 26470 uses a chronograph layout with small seconds, a 30-minute counter and a 12-hour counter, and the date sits at 3 o'clock.

Check 4: Movement and caseback

Most 26470 references use a sapphire display caseback, so you can inspect the movement directly. If the watch in front of you has a solid back where the reference should show the movement, that alone ends the conversation.

The calibre 3126/3840 family is finished to a high standard: Cotes de Geneve on the bridges, circular graining, polished and chamfered edges, blued or polished screws with proper heads, and a gold rotor with deeply engraved lettering. A replica movement, usually a modified third-party chronograph or a decorated clone, shows shallow engraving, a rotor that is too light, wrong screw heads, or a jewel count and beat rate that does not match. The published specification for this calibre line is 59 jewels, about 365 components and 21,600 vibrations per hour, so ask for a timegrapher reading and compare.

Function test: start, stop and reset the chronograph several times. The reset should snap to zero instantly. A sluggish sweep or a pointer that overshoots and drifts back points to a cheap module.

Check 5: Serial numbers, engraving and paperwork

Reference and serial engravings are laser cut with consistent depth and sharp edges. Look for the reference number in the form 26470ST, 26470OR or similar, followed by the full configuration code, plus a serial that matches any documentation you were given.

• Genuine: sharp engraving, no double lines, correct font weight, matching numbers across paperwork.
• Fake: shallow or dotted engraving, wrong letterforms, a serial that does not appear on the card, or a certificate printed on stock paper with generic fonts.

Paperwork proves very little on its own. Boxes, cards and even dealer receipts can be reproduced, so treat them as supporting evidence and not the deciding factor.

What even the best clones still get wrong

High-end replicas have closed the gap on dials and outward appearance. The gaps that remain are mechanical and tactile: movement architecture and finish, total weight from the gold rotor, case thickness, bezel screw machining, and the feel of the chronograph. Those four items are where an expert will always look first, and they are the hardest things to fake at scale.

Where to get a real answer

Visual checks narrow the field, but they do not replace a bench inspection. A watchmaker with an AP parts account can open the case, measure the movement, check the jewels and confirm the numbers. An authorized Audemars Piguet service center can confirm the watch when it is presented for servicing. If a seller resists an inspection, or prices a 26470 far below the market for the reference and condition, stop there. No legitimate sale depends on you skipping verification.

Quick recommendation by situation

• Buying privately: do not send money until a watchmaker has opened the watch and photographed the movement and serials.
• Buying from a dealer: ask for the reference code in writing, a service history, and a return window long enough for an independent inspection.
• Checking your own watch: compare the bezel screws and case chamfers first, then have the movement photographed at the next service.
• Selling one: request an authenticity statement from a watchmaker or service center before listing, because buyers of this reference will ask for one.