The GMT Master watch was originally designed for pilots because the watch simultaneously displays the time in three different time zones. The GMT Master II is an automatic watch, which means it winds automatically when worn or placed in a watch winder. It features a Twinlock seal on the crown that makes it waterproof up to depths of 330 feet.
Twist the crown counterclockwise until it pops out. Once the crown is popped out, it is in position one, where you can turn the crown clockwise and manually wind the watch. You want to do this if you have not worn the watch for a couple of days and the watch has stopped.
Pull the crown out one notch to position two. At this position you can turn the crown to adjust the hour hand, the small hand with the circle at the end. Keep the hour hand set to your home time zone.
Pull the crown out another notch to position three. At this position, you can move the crown in either direction and adjust the minute hand. Moving the minute hand will also adjust the date function. Unlike most Rolex watches with the date feature, the GMT II does not have the "quick set" date option where you can adjust the date without having to move the minute or hour hand.
Moving the crown in position 3 will also move the 24 hour hand, which is the colored hand with the arrow at the end. This hand should be set to Greenwich Mean Time, GMT. This feature is helpful to pilots because all time zones are centered around GMT. For example, New York is GMT -5 because the time in New York is five hours behind London.
Rotate the bezel, the ceramic piece surrounding the face of the watch, to quickly change the time without actually adjusting the hour hand. The bezel has numbers around it representing the 24 hours in the day. For example, if you had your hour hand set to 6 p.m. New York time and you flew to Phoenix, which is two hours behind New York, you can rotate your bezel so the "4" on the bezel is matched up with the hour hand. Now you can read that it is 4 p.m. in Phoenix, 6 p.m. in New York and 11 p.m. in London on Greenwich Mean Time.
Push the crown in past position one and turn it clockwise while pressing down to close the crown. The crown should be tight to ensure it is waterproof.
You will need to change the date at the end of months shorter than 31 days because the date is programmed to show 31 days every month.