Short answer
126719 is the Rolex case reference for a GMT-Master II in 18k white gold, 40 mm. The suffix BLRO on the genuine watch means a blue and red bezel insert. BLSO does not appear in Rolex catalogs. It shows up in replica listing titles, where sellers stack extra letters onto the reference. Treat the last four characters as seller text, not factory code.
Genuine reference facts
- Case: 40 mm, 18k white gold, Oyster case
- Bezel: blue and red Cerachrom insert, 24-hour scale, platinum-filled numerals
- Movement: caliber 3285, 70-hour power reserve, 28,800 vph
- Dial options: black lacquer or meteorite
- Bracelet: white gold Oyster, Oysterlock clasp
- Water resistance: 100 m
- US retail: about USD 40,000 to 43,000 depending on dial
Where replicas differ
Case metal and weight. Most replicas of the 126719 use 316L or 904L steel. Some use a tungsten alloy to add heft. A steel GMT on a full bracelet weighs about 150 g. A white gold one runs about 200 g. Weight is the first check, and a kitchen scale settles it.
Bezel insert. The genuine Cerachrom insert is one ceramic piece. Replica inserts often show a mold seam at 12 or 6 o'clock, uneven color at the blue-red transition, and painted numerals that wear. Genuine numerals are filled with platinum by a PVD process and sit flush.
Movement. Replica 3285 copies run at 28,800 vph with a true jumping hour hand. Lower-grade builds use a 2836 base with a GMT module. On those, the hour hand does not jump independently and the crown positions feel soft.
Dial. Meteorite dials carry a Widmanstätten crystal pattern. No two genuine dials match. Replica meteorite dials use a printed or stamped pattern that repeats across units, and the etch lines look shallow under a loupe.
Legal status in the US
Counterfeit watches are illegal to import and to sell. US Customs and Border Protection seizes shipments, and selling a replica as genuine is trademark counterfeiting. Purchase for personal use is not a federal crime in most cases, but the item can be seized, and Rolex will not service or authenticate it. Resale value is zero.
What a listing should state
- Case metal and any plating thickness
- Movement name, base caliber, and beat rate
- Case weight in grams
- Water resistance, tested or claimed
- Return window and who pays return shipping
A listing that omits case weight and movement base is telling you what you need to know.