Introduced in 1955 following a request from Pan Am airlines for a wristwatch that could simultaneously track multiple time zones, the GMT-Master features a 24-hour hand accompanying a 24-hour bezel that could be rotated to track a second time zone. In 1982, Rolex introduced the GMT-Master II, whose 24-hour hand could be adjusted independently from the other hands, thus allowing a third time zone to be tracked. Today, the GMT-Master II is hailed as the ultimate cosmopolitan watch, and its bicoloured bezel remains an icon of Rolex.