What are GMT watches?
GMT watches are watches that have multiple time zones, usually watches that the second time zone set to GMT. GMT means that Greenwich Meridian Time, and is standard on which all time is kept. The world was divided into 24 different time zones, starting at Greenwich, England. This was done because at the time world's time zones where not standardize and communication and travel had become so much more available that standard time zone became a must. Good thing too, I would not want to travel to the next town and be in a different time zone.

So who uses GMT watches?
The most common use for GMT watches are pilots. Since they travel so much having two time zones on your watch can be very valuable. The over main use is for travelers and business men. They are constantly traveling, so having a GMT watch with multiple time zones can be very valuable to them. I wonder if astronauts use GMT watches, that would be kind of cool.

So I want a GMT watch, is going to cost an arm and a leg?
No, you can actually get a GMT watch for under ten dollars at ebay. It probably will not be the best quality but it will do its job. So I would not worry about it.

I really like luxury watches, do they make GMT luxury watches?
Yes in fact Rolex makes quite a few GMT watches and so does Patek Phillipe. Both these brands are incredibly expensive and beautiful. There are also more medium price GMT watches, like Citizen and Timex, which will cost around $500 or so.

How do I set a GMT watch?
This is something that a lot of watch lover struggle with. I would always recommend looking at the instructions, but usually you first set the secondary second hand follow by the primary second hand of the watch. Congratulations, you now have two time zones.