GMT

Definition

A second time zone shown on the same dial, most often by an additional hour hand that turns once in 24 hours and reads against a 24-hour scale on the bezel or the dial's edge. The name comes from Greenwich Mean Time, the reference the original Rolex GMT-Master of 1955 was built to show for Pan Am crews. The useful distinction is which hand adjusts: on a "true" GMT the local hour hand jumps in one-hour steps from the crown so that a traveller resets it on landing, while on the simpler "caller" type the 24-hour hand is the one that moves. The Rolex 9002 and the Breitling B04 are the first kind; the Breitling Caliber 32 is the second. Panerai fits it to more of its range than most, with 57 GMT references in the Radiomir alone.