The best replica Omega 3320 build is the one with an ETA 2892-A2 or Sellita SW300 under the caseback, because that is the architecture the real caliber sits on. A Seagull ST1812 delivers most of the look for a fraction of the cost and can be swapped for a Swiss movement later, while Miyota 9015 builds trade decoration accuracy for reliability. The criteria below cover movement platform, thickness and beat rate, case and dial fidelity, crown and tube quality, bracelet fit, and how to verify a listing before money changes hands.

What the 3320 reference actually describes

On a genuine Omega, caliber 3320 is a chronometer-rated automatic from the ETA 2892 family: thin, 28,800 vibrations per hour, central rotor, sweep seconds, and a date window at three. In the replica market the number gets reused loosely. Listings stamped "3320" turn up holding Chinese 2892 copies, ETA 2824 clones, and occasionally decorated quartz. That mismatch is the main reason two watches that look identical in photos feel completely different on the wrist.

Option 1: ETA 2892-A2 base

  • Pros: correct architecture for the 3320 lineage, 3.6 mm thick, 21 jewels, roughly 42 hours of power reserve, smooth hand winding, parts available at most watchmakers.
  • Cons: the most expensive route, and many listings claiming a "Swiss 2892" are relabeled clones, so paperwork and movement photos matter.

Use case: buy this if the watch is a long-term keeper and you want a movement any competent watchmaker can service.

Option 2: Sellita SW300

  • Pros: Swiss made, 25 jewels, built as a 2892-2 compatible replacement, so dial feet, hand sizes, and stem height line up with real 2892 cases.
  • Cons: slight date wheel position differences on some batches, supply fluctuates, and it carries a price premium over the Chinese equivalents.

Use case: the pick for someone who wants Swiss reliability without hunting for a genuine ETA.

Option 3: Seagull ST1812

  • Pros: shares the 2892 footprint and thin profile, beats at 28,800 vph, costs a fraction of Swiss options, and drops straight into a case built for a 2892.
  • Cons: rougher finishing, audible rotor, real-world power reserve often lands under the claimed figure, and quality varies between batches.

Use case: the value choice for a first 3320 replica or a watch you plan to upgrade with a Swiss movement later.

Option 4: Miyota 9015

  • Pros: dependable, accurate out of the box, 28,800 vph, thin enough for a slim case, and easy to replace.
  • Cons: no 2892 lineage, so hand and dial spacing can differ, the rotor is noticeably loud, and date change direction and stem height may not match the case design.

Use case: a daily wearer where reliability beats cosmetic correctness.

Criterion: case and dial fidelity

  • Pros of a good build: case sides mirror the original profile, bezel action is crisp with no back play, dial printing is sharp under a loupe, and lume plots sit evenly.
  • Cons of a weak build: fat lugs, soft bezel knurling, printed markers that fade at the edges, and a rehaut depth that reads wrong from any angle.

Criterion: crown, tube, and water resistance

  • Pros: a screw-down crown that seats with light pressure, a smooth stem with no grinding, and gaskets that hold pressure in a basic tester.
  • Cons: cross-threaded tubes, crowns that back out on their own, and listings that advertise dive depth while shipping dry gaskets.

Treat any claimed depth rating as unverified until a watchmaker pressure tests the case. Swimming in an untested replica is how movements rust.

Criterion: bracelet and end links

  • Pros: solid end links flush with the lugs, tight screw or pin fit, a clasp that closes with one hand, and no rattle when shaken.
  • Cons: hollow end links with gaps, sharp bracelet edges, and clasps that lose tension within weeks.

How to verify a listing before buying

  1. Ask for a movement photo with the caseback off, not a stock catalog image.
  2. Ask for the beat rate on a timegrapher readout. A 2892 family movement shows 28,800 vph.
  3. Confirm case diameter, thickness, and lug width against the reference you want.
  4. Check the return policy in writing, and pay with a method that allows a dispute.

One legal note worth knowing: in the United States, trafficking in counterfeit goods is illegal, and shipments can be seized by customs. Buyers should understand the risk before ordering.

Which one to choose

  • Long-term keeper with service support: ETA 2892-A2 or Sellita SW300.
  • Best value for the look: Seagull ST1812.
  • Daily beater: Miyota 9015.
  • First purchase from an unknown seller: start with the cheapest credible movement platform and spend the savings on a watchmaker inspection.