The GMT Master was designed historically with Pan-Am airline pilots in mind as they needed to refer to the GMT (Greenwich meridian time) during flights and wanted to keep track of the local time as well.

Rolex hence created a caliber of watches which had an extra (fixed and non adjustable) 24-hour hand and a rotatable bezel which one could set to the time zone one wants to keep track off. They called this watch the GMT Master.

Moving forwards, an upgraded version of this model, the GMT Master II, was introduced, and this had a 24-hour hand which was independently adjustable hence allowing you to keep track of three time zones in total. Most users would then keep the 24-hour hand on the GMT-time and set the 12-hour hand to the local time.

When purchasing a replica Rolex GMT-Master II, bear in mind that most run of the mill sites do not carry the more accurate models that spot the independently adjustable GMT hand.  Before making a purchase, always check and ensure that the watch you are purchasing has this function.  They should be available in top grade Japanese, Italian and Swiss movement replicas. 

The GMT hand moves 2 times slower than the usual hour hand. It makes a full cycle in 24 hours instead of 12 hours which the normal hour hand takes. This allows you to use it hence to tell the time in a separate time zone.

To adjust the GMT hand, you will need to unscrew the crown to the date-set position and turn the crown ANTI-CLOCKWISE (in the opposite direction from setting the date).  Practically, it is not absolutely necessary to adjust the GMT hand as you can simply turn and adjust the 24 hour bezel to the desired time zone position to match your GMT hand. 

The GMT Master II is available in both stainless steel, 2 toned and full gold versions, and there is a choice of bezel colors (blue/red, black/red and full black). There is a limited edition version made with a white dial which was released for Pan-Am in the past, but these are very rare. 

We have included front shots of a swiss-made high end replica and a Japanese-made Pepsi (red / blue) GMT-Master II for side-by-side comparison.

   
 Swiss model                                                     Japanese model

The watches are generally very similar, but if you look closely at the swiss model, you will notice some subtle physical differences, including the following:

a. ROLEX font on dial is more proportionate and closer to the genuine article
b. Font of numbers on bezel resembles closer to the genuine watch
c. Size of GMT hand more closely resembles the genuine watch

The hollow link Oyster bracelet is one of the best parts of this watch. After polishing, oiling and giving it a new brushed finish it is virtually indistinguishable from the genuine. In some reps you have to file the edges smoother, too. The "treated" bracelet feels silky, light, flimsy and cheap. i.e exactly like the real one. The GMT’s band is even lighter than Submariner’s band because it has a shorter clasp (like the Explorer) without the diver’s extension. Do not be surprised therefore when you receive your first replica Rolex. Just remember that the genuine Oyster band is just as light. A side note: Genuine Master II (with all links intact) weighs 127 grams. The rep weight is exactly similar +/- 2 grams.

For a swiss-made Rolex GMT Master II, visit http://www.swissqualitywatchez.com/GMTMaster/
GMT-Master-Stainless-Steel-All-black-bezel-black-dial.html

For a Japanese-made Rolex GMT Master II, visit
http://www.monsterrolex.com/Rolex-Sports-Models/GMT-Master-II-SS.html