Designed to show the time in two different time zones simultaneously the GMT-Master launched in 1955 was originally developed as a navigation instrument for professionals criss-crossing the globe.

In addition to conventional hour minute and seconds hands the GMT-Master II features an arrow-tipped hand which circles the dial once every 24 hours as well as a bidirectional rotatable 24-hour graduated bezel.

With traditional hour minute and seconds hands a triangle-tipped 24-hour hand and a bidirectional rotatable bezel with 24-hour graduated Cerachrom insert the GMT-Master II can display the time in two time zones simultaneously: either the local time and the reference time or the local time and that of an alternative time zone. The date at 3 o'clock on the dial is synchronized with the local time.