A GMTGMT A GMT (Greenwich Mean Time) complication is a feature found in some watches that allows the wearer to track two time zones simultaneously. It typically includes a 24-hour hand and a bezel or a second hour hand that can be adjusted independently of the main hour hand to track the time in a different time zone. [Learn More] (Greenwich Mean Time) complication is a feature found in some watches that allows the wearer to track two time zones simultaneously. It typically includes a 24-hour hand and a bezel or a second hour hand that can be adjusted independently of the main hour hand to track the time in a different time zone.