Short answer: a replica of the ref. 26470 stands or falls on three measurements and one dial layout. The case should read 42 mm across and about 14.6 mm thick, the dial should carry chronograph sub-dials at 12, 6, and 9 with the date at 3, and the movement should behave like a 3 Hz caliber when you run the chronograph. A copy that misses those points is a different watch wearing an Offshore bezel.

Prerequisites

  • Digital calipers with 0.1 mm resolution
  • A 10x loupe or a macro lens for phone photos
  • Reference photos of a genuine 26470 from auction listings or brand catalog images
  • A seller who states a return window in writing

Learn the genuine reference numbers

The 26470 runs the caliber 3126/3840, a modular chronograph built on the 3120 base, with a 50 hour power reserve and 21,600 vibrations per hour. The case is stainless steel at 42 mm, water resistant to 100 m, with a sapphire crystal and a rubber or alligator strap on a folding clasp. Keep those figures in front of you while you inspect a replica, because sellers borrow the brand language and rarely publish their own numbers.

Measure the case and bezel

  1. Close the calipers across the bezel from the 9 to the 3 position and write the diameter down.
  2. Measure from the center of the caseback to the highest point of the crystal for total thickness.
  3. Check the eight bezel screws for a slot deep enough to take a driver and a head that sits even with the bezel surface.
  4. Look at the crown and pusher guards and confirm they sit in the case flank without gaps at the seals.

Compare the dial

  1. Confirm sub-dials at 12, 6, and 9 with the date aperture at 3.
  2. Inspect the Mega Tapisserie grid and check that the squares are crisp, uniform, and level with the dial surface.
  3. Read the date wheel font and the position of the numeral inside the window.
  4. Verify the hands, which should be broad with lume applied inside the frames, and match the hand stack order when you set the time.

Test the movement behavior

  1. Start the chronograph and watch the center seconds hand, which should advance six times per second on a 3 Hz movement.
  2. Reset the chronograph and confirm the hand returns to 12 without drift.
  3. Set the time and note whether the date changes near midnight or hours later.
  4. Hold the watch next to your ear and listen to the rotor, since a rough scrape points to a low grade automatic.

Confirm the seller terms

  1. Ask for the return window and refund terms in writing before payment.
  2. Request photos of the exact watch rather than stock images of the model.
  3. Ask which movement is installed and keep the answer in a saved message.
  4. Pay with a method that allows a dispute if the watch arrives outside the stated specs.

No replica carries a genuine 3126/3840, and no inspection changes that. The value of these steps is comparison, so you can rank one copy against another and against the published reference specs. Buy only when the seller's measurements and return terms hold up.