Answer First: Fix the Reference Number
Listings that advertise a "Rolex 1666" or "1666 6 copy" are keyword mashups. Rolex never produced a reference 1666. The watch behind that search term is the Submariner Date 16610, built from 1988 to 2010. Before you spend anything, confirm the seller is describing a 16610 case: 40mm bezel diameter, roughly 12.5mm thick, 20mm lugs, and a lug-to-lug span near 47mm. If the measurements are wrong or the seller cannot state them, nothing else in the listing matters.
What to Look For
Case and profile
Ask for caliper photos instead of wrist shots. A 16610 copy should sit close to 12.5mm thick including the caseback. Anything past 13.5mm often hides a low-grade automatic and a thick gasket stack. Study the crown guards: they should taper into the case with a soft curve, not a boxy slab. Lug holes, if present, should line up with the spring bars and match the era the seller claims to copy.
Movement
Movement type drives most of the price gap and most of the reliability. An Asian 2824 or 2836 clone is the practical baseline and any competent watchmaker can regulate it. Clones of the 3135 offer a correct hand stack and a smoother sweep, but parts are scarce and service costs climb. Ask for a timegrapher reading showing rate and amplitude rather than a claim on a spec sheet.
Dial, hands, and bezel insert
Check the font weight on the dial text, the alignment of the coronet at 12, and the spacing of the minute track. Bezels should click through 120 positions with firm detents and no back play. The pearl at 12 should sit centered in the triangle, not offset to one side. Hands should reach the minute track without overhang.
Crystal and date magnification
The cyclops should magnify the date to roughly 2.5x and sit centered over the window. A weak or cloudy cyclops is the fastest tell on a cheap build. Sapphire with a proper anti-reflective coating is the standard at mid tier and above; mineral glass scratches and distorts at the edges.
Bracelet and clasp
Solid end links that fit flush against the case are worth more than any marketing label. Check the clasp stamps, the safety fold, and whether the links articulate without squeaking. Hollow mid-links feel light and rattle, which is correct for some vintage references and wrong for a modern copy.
Parameter Bands
- Entry tier: generic Asian automatic, stamped clasp, hollow end links, mineral glass, flat bezel pearl. Expect several seconds of daily drift and no meaningful water resistance.
- Mid tier: Asian ETA clone, solid end links, sapphire crystal, clean dial print. Serviceable by a local watchmaker who works on clone movements.
- Upper tier: decorated 3135 clone, correct hand stack, refined case finishing, bracelet with a proper glide-lock style adjustment. Still a copy, still not a genuine movement.
Ignore the phrase "Swiss made" unless the seller names the movement and shows it running. A Swiss ETA claim attached to an inexpensive listing is a contradiction, not a feature.
Pitfalls
- Stock photos. If the seller will not send dated pictures of the actual piece, assume you will receive something else.
- Invented references. 1666 and "1666 6" signal a scraped listing built for search traffic.
- Water resistance claims. Unless the case has been pressure tested, keep it out of water.
- Gold plating. Two-tone copies wear through at the clasp and crown within months of daily wear.
- Weight claims. Sellers quote grams to imply solid gold, but weighted steel can be made to match.
Legal Reality in the United States
Counterfeit watches infringe trademarks. Importing or selling them is illegal in the US, and shipments can be seized and destroyed. That exposure falls on the buyer as well as the seller, so treat it as a real cost of the transaction and not a footnote. Budget your expectations around that risk before anything else.
FAQ
Can a replica pass as genuine?
No. A watchmaker with a loupe will spot the movement, the dial print, and the case finishing. Treat a copy as a lookalike, never a substitute.
Which movement should I expect?
An Asian 2824 or 2836 clone is the working baseline. A 3135 clone gives a smoother sweep and a correct hand stack, but it costs more and is harder to repair.
How often does a clone movement need service?
Every three to five years with daily wear, and parts availability is the weak point. Many owners swap the whole movement instead of repairing it.
Is the 16610 the only Submariner worth copying?
No. The 14060, 16800, and 16613 are common targets, and each has its own proportions. Compare any copy against the exact reference it claims to be.