Quick answer

A genuine Rolex GMT-Master II 16710 "Pepsi" has an aluminum bezel insert with blue and red halves, a 40mm steel case, and a movement that hacks with an independently settable 24-hour hand. If the bezel is ceramic, or the date magnifier looks flat, or the GMT hand sits above the minute hand, you are looking at a fake. The fastest single test is the bezel: Rolex did not put a ceramic Pepsi bezel on any watch until 2014, and that watch was white gold, not the steel 16710.

What the real 16710 actually is

The 16710 replaced the 16760 in 1989 and stayed in the catalog until 2007. It is a 40mm steel GMT-Master II, roughly 12mm thick, with 20mm lugs and a Twinlock crown. Early examples have drilled lug holes; later ones do not. Inside is the caliber 3185, and the final years of production used the 3186. Both movements hack, both have a quickset date, and both let you set the 24-hour hand on its own without stopping the watch.

Three inserts were sold for this reference: Pepsi (blue and red), Coke (black and red), and plain black. Owners swapped them, which is why you see so many combinations today. The bezel is bidirectional with 24 clicks. That detail matters, because a unidirectional bezel with 120 clicks is a Submariner part, not a GMT part.

Bezel insert tells

  • Material. The 16710 insert is anodized aluminum with a matte surface and no gloss. Ceramic is wrong for this reference.
  • Numerals. The insert font is thin with a hint of serif. Fakes print thick, blocky numerals, or run the red too far into the blue half.
  • The 24 pip. A lume pearl set inside a triangle at the top. On tritium-era watches the pearl ages to a warm cream. On later ones it stays white.
  • Color split. The line between blue and red sits at the 6 and 18 positions. On a fake it drifts or sits crooked.
  • Fit. The insert should sit flush in the bezel ring with an even gap all the way around.

Case, lugs, and engravings

Measure it. A 41mm case or a 13mm thick case is a fake no matter what the listing says. The lug profile on the 16710 is slim and tapers, and the crown guards are short and rounded.

Pull the bracelet back and look between the lugs. The reference number sits at 12 and the serial at 6, both engraved into the case. The font is small and crisp. Replicas either skip this, use a laser etch that looks burned, or stamp a serial that does not match the production era of the dial.

The caseback is plain. No engraving on the outside, no display back, no deep stamping. A display caseback on a 16710 is a red flag on its own.

Dial, hands, and crystal

  • Dial text. "ROLEX OYSTER PERPETUAL DATE GMT-MASTER II" with "SUPERLATIVE CHRONOMETER OFFICIALLY CERTIFIED" below the hands. Spacing and thickness matter more than people expect.
  • Lume era. Tritium dials run to about 1998 and are marked "SWISS - T < 25" at 6. After that you get Luminova, then Super-LumiNova, marked "SWISS MADE."
  • Hand stack. From the dial up: hour, GMT, minute, seconds. Plenty of replicas put the GMT hand on top because the base movement forces it. That is one of the easiest tells to catch in a profile photo.
  • GMT hand. A broad arrow with a red shaft. The hour hand is the Mercedes style and the minute hand is a baton.
  • Crystal. Sapphire with a cyclops at 3. Magnification runs about 2.5x and the date sits centered under it. A weak cyclops or an off-center date is a fake.

Bracelet and clasp

The 16710 came on a 20mm Oyster bracelet, most often a 78790 or 78790A with solid end links. The end links should sit tight against the case with no visible step or gap. On the clasp, check the depth and font of the stamping. Replica clasps tend to have shallow stamps, a wrong coronet, or a "STEELINOX" mark that looks laser printed instead of struck.

Movement checks you can do without opening the case

  1. Pull the crown to the first position and turn. The date should snap over in one clean jump.
  2. Set the 24-hour hand on its own. If it drags the minute hand with it, it is not a 3185 or 3186.
  3. Check hacking. Pull the crown all the way out and the seconds should stop.
  4. Listen to the beat. A 4 Hz movement runs at 28,800 vph, or eight beats per second. Cheap replicas often run at six.
  5. Feel the wind. A real 3185 winds smooth and returns a firm, dry feel. Gritty or springy points to a clone or an ETA base.

Price reality

A clean, complete 16710 Pepsi trades in five figures in US dollars, and a full set with box and papers adds a premium on top. That number alone filters out most fraud. If the price is a few hundred dollars, or the seller calls it "Swiss made" and shows a ceramic Pepsi insert, you already have your answer. Ask for a movement photo, a between-the-lugs photo, and a serial number, then have a watchmaker open it or send it to a Rolex service center for a service estimate before money changes hands.

Bottom line

Start with the bezel material, then the hand stack, then the case measurements and the engravings between the lugs. Those four checks catch almost every fake 16710 Pepsi you will run into. Everything else, the dial font, the cyclops, the bracelet, is confirmation.