Top pick for most buyers is a vintage-spec super clone built on a 3135-pattern movement, with a sapphire crystal, a working helium escape valve, and a 40 mm case that lands close to 15 mm thick. That tier is the only one where the case profile, dial text, and bezel insert line up with a real reference 16660. The options below are ranked on six points: case shape and thickness, crystal material, bezel insert and click, dial markings and font, movement, and bracelet end link fit. Those are the places a 16660 replica gives itself away first.
The Six Points That Decide a 16660 Replica
- Case: 40 mm across, roughly 15 mm thick, 20 mm lugs, crown guards at 3 o'clock, helium escape valve at 9 o'clock. Anything measuring 16 mm or more reads slab-sided on the wrist.
- Crystal: The 16660 was the first Sea-Dweller to run sapphire. A tall domed acrylic crystal usually means the builder copied an earlier 1665 case and never corrected it.
- Bezel: Coin-edge grip, 60-minute insert, tritium-toned pearl. The click should feel firm with no back play when you rock the bezel by hand.
- Dial: Matte black, no cyclops over the date, lume plots that sit near the rehaut. Many early 16660 dials still carry the older Submariner 2000ft = 610m line even though the watch is rated to 1,220 m.
- Movement: The original ran a 3035 and later a 3135. Replicas run a 3135 clone, an ETA 2836-2, an Asian 2836-2, or a Miyota 8215.
- Bracelet: Oyster 93150 style with 585 end links and a flip-lock clasp. End links should sit flush against the case with no light showing through the gap.
Option 1: Vintage-Spec Super Clone (Best Overall)
This is the tier where the builder starts from the 16660 rather than adapting a Submariner case. You get a sapphire crystal, a case flank thick enough to house a real helium escape valve, drilled lugs, and a date wheel without the magnifier. The 3135-pattern movement also gives you a quickset date, which the older 3035-style setups often get wrong.
Pros
- Case dimensions land within a fraction of a millimeter of the reference.
- Sapphire crystal and a functioning helium escape valve crown.
- Correct no-cyclops date at 3 o'clock with the right window bevel.
- Drilled lugs and a bracelet that matches the case finish.
Cons
- Highest price band of the three options.
- Batch variance, so two examples of the same build can differ on dial font and bezel pip alignment.
- Some builders over-polish the case and lose the sharp lug bevels.
Buy it if: you want a daily wearer that survives a close look across a dinner table, and you plan to keep it on a NATO or a rubber strap for swimming.
Option 2: Mid-Tier Build With an ETA or Asian 2836
This is the practical middle. The movement is a known quantity, parts and servicing are easy to source, and the watch keeps time without drama. The trade-off shows up in the geometry: the 2836 sits differently in the case, so the date window, hand stack height, and crown position rarely match the original layout.
Pros
- Reliable, serviceable movement with a wide parts network.
- Notably cheaper than the vintage-spec tier.
- Reads correctly at arm's length and in photos.
Cons
- Case is often 1 to 1.5 mm too thick.
- Date font and window shape are usually off.
- Bezel insert pearl position and lume color drift from the original.
- End link fitment can leave visible gaps at the lugs.
Buy it if: you want a reliable automatic diver for weekend wear and you are not chasing reference accuracy.
Option 3: Entry-Level Automatic
The cheapest tier exists to look right from three feet away. The case is a generic 40 mm diver shape, the bezel is stamped, and the helium escape valve is usually a decorative plug with a glued-on crown. It still tells time, and it still takes a strap.
Pros
- Lowest cost by a wide margin.
- Light on the wrist and cheap to replace.
- Fine as a beater for yard work or a costume build.
Cons
- Painted lume that fades to gray instead of aging to a warm tone.
- Hollow end links and a rattling clasp.
- Dial text spacing and font weight are noticeably wrong under close inspection.
- Crown threads wear out fast if you reset the time often.
Buy it if: you want the Sea-Dweller silhouette for a specific outfit or event and accuracy does not matter to you.
One last note before you order. The 16660 left the catalog in the late 1980s, so original watches are scarce and original parts are scarcer. Ask the seller for the case thickness in millimeters, the crystal material, and the exact movement before you commit. If a listing cannot answer those three questions, move to the next option on the list.