Quick answer
A replica Explorer II 16570 holds up only when it copies four things: the 40 mm case, a thickness near 12.2 mm, the fixed 24-hour bezel, and the correct GMT hand stack. Check those four first. A build that fails any of them will look wrong on the wrist no matter how clean the dial photos look.
The genuine baseline
Rolex built the Explorer II 16570 from 1989 to 2011. The steel case measures 40 mm across, with a 20 mm lug width and a 100 m water rating. The bezel is fixed and marked for 24 hours. The crystal is sapphire with a cyclops over the date at 3 o'clock. Inside sits the calibre 3185, replaced by the 3186 in the last years of production. On both movements the hour hand jumps in one-hour steps at the second crown position, and the GMT hand sets at the first crown position. Keep that behavior in mind. It is the hardest part of the watch to fake.
Prerequisites
- Digital calipers that read to 0.01 mm
- A 10x loupe
- A small screwdriver and a bracelet sizing tool
- Reference photos of a genuine 16570 dial and bezel
- A watchmaker who can pressure test the case
How to inspect a replica 16570
- Measure the case with calipers. Read the diameter at the bezel edge and the thickness from caseback to crystal. Accept 40 mm and 12.2 mm, with a tolerance of about 0.3 mm. Replicas sold as 39 mm or 41 mm use a different case, and thick cases sit tall on the wrist.
- Check the lug width and end links. The gap between the lugs should measure 20 mm. End links should meet the case with no visible step or gap.
- Read the bezel numerals. The 24-hour scale is engraved into steel and filled with black paint. Numerals on a good replica have sharp cut edges and even spacing. Painted-on or shallow laser markings smudge under a loupe.
- Inspect the dial print. The coronet at 12 sits centered above ROLEX and OYSTER PERPETUAL. Marker surrounds are white gold on the genuine watch, so they catch light at an angle. Lume plots should sit level and hold the same fill depth on every marker.
- Look at the date window and cyclops. The date sits at 3 o'clock under a magnifier at about 2.5x. A cyclops with a visible glue ring, or a date that sits low in the window, is a giveaway.
- Test the hand stack. Unscrew the crown and pull to the first position. The GMT hand should set on its own. Push to the second position. The hour hand should jump in one-hour steps, and the date should flip when the hands pass midnight. If the GMT hand only sweeps once per 24 hours with the minute hand, the movement is a standard clone with an added hand.
- Wind and set the crown. Threads should engage without grit or grinding. A crown that wobbles or cross-threads will fail before the movement does.
- Check the bracelet and clasp. The clasp should close with a firm click, and the coronet stamp should be crisp. Stretch the bracelet and look for gaps between the links.
- Read the caseback and lug engraving. Reference and serial numbers between the lugs should be stamped, not printed or lasered. Stamping leaves depth that catches light at a low angle.
- Pressure test the case. Ask a watchmaker for a 100 m test. Skip this step and you risk water in a watch rated for swimming.
- Time it for 24 hours. A decent clone should hold within about 15 seconds a day. Worse than that points to a cheap movement or poor regulation.
Quality tiers to expect
Budget builds use a 39 mm or 41 mm case, printed bezel markings, and a movement with a fake GMT function. Mid tier builds get the 40 mm case right but often miss the case thickness or use flat lume. The top tier, sold as 1:1, copies the case profile, uses a 3185 or 3186 clone, and fits a bracelet with solid end links. Spend your attention on the case and the hand stack, since those cannot be fixed after purchase.
Red flags
- Seller photos that avoid the crown side and the caseback
- No pressure test offered
- Case thickness listed as about 13 mm, or left out
- Bezel numerals that look flat in a close-up
- Date font that is too thick or sits low in the window