What a Replica Rolex 16660 Refers To

The Rolex 16660 is the Sea-Dweller that Rolex built from about 1978 to 1988. Collectors call it the "Triple Six." A replica 16660 is a third-party copy of that watch, sold under labels such as first copy, mirror grade, or AAA. The reference matters because the 16660 is the turning point in the Sea-Dweller line. It moved the model to sapphire crystal, raised the depth rating to 1,220 m, and brought in the caliber 3035 with a quick-set date. A copy stands or falls on those three details.

Reference Facts to Compare Against

  • Case: 40 mm steel, a thicker mid-case than a Submariner, drilled lugs on early examples.
  • Depth rating: 1,220 m / 4,000 ft, printed on the dial as a depth line, not as model text only.
  • Crystal: flat sapphire with no magnifier over the date.
  • Movement: Rolex caliber 3035, 27 jewels, 28,800 vph.
  • Valve: helium escape valve at 9 o'clock.
  • Bezel: ratcheting diver's bezel with a lume pip at 12.
  • Dial eras: matte black with painted markers on early runs, gloss black with white gold surrounds from the mid-1980s.

Prerequisites Before You Compare

  • Pick the era you want, matte dial or gloss dial, so you are not mixing details from two periods.
  • Get straight-on and profile photos of a genuine 16660 from a catalog or auction archive.
  • Set your budget tier in advance. Case work, crystal, and movement type are where the tiers separate.

How to Evaluate a First Copy 16660

  1. Measure the case across the crown guards. A 16660 measures 40 mm, and many copies run wider.
  2. Check the case profile from the side. The Sea-Dweller case is thick, with a flat case back that sits high on the wrist.
  3. Inspect the crystal. It should be flat sapphire, and there should be no cyclops lens over the date window.
  4. Read the dial text under a loupe. Confirm the depth line, the model name, and the chronometer line are correctly placed and spaced.
  5. Examine the helium escape valve at 9 o'clock. On the real watch it is a one-way self-actuating valve that sits flush with the case flank. On cheap copies it is a decorative cap with no function.
  6. Look at the date window. Run the crown through a full month. Caliber 3035 offers quick-set, so the date should jump cleanly rather than drift.
  7. Time the sweep. A genuine 3035 beats at 28,800 vph. Many budget copies run at 21,600 vph, which shows as a slower sweep.
  8. Weigh the head. Steel density and case thickness put the genuine watch well above the lightest copies.
  9. Check the bracelet end links against the lug width. Gaps and wobble are the most common tell on a first copy.

Red Flags

  • A date magnifier. The 16660 has none. If you see a cyclops, the watch is not replicating the reference.
  • Photos that only show the dial. Case profile and lug shape carry most of the identification.
  • Model text with the wrong depth figure, such as 610 m or 300 m.
  • A crown that does not screw down or a bezel that turns without detents.

Legal and Practical Notes

Counterfeit watches that carry a protected trademark cannot be imported into the United States or sold here. US Customs and Border Protection can seize shipments, and sellers face civil claims from the trademark owner. On the practical side, a copy has no factory service path, no parts supply, and no resale market. Buy on those terms or not at all.