Rolex 1066

The Rolex Caliber 1066 is the celebrated movement that powered the original Rolex GMT-Master, reference 6542, starting in 1955. Developed for Pan American Airways pilots at the dawn of the jet age, this caliber was a technical achievement of its time. Based on the chronometer-grade Caliber 1030 architecture, the 1066 added a date function and a signature 24-hour hand complication. This fourth hand was geared to the main hour hand and completed a single rotation every 24 hours, pointing to a corresponding 24-hour scale on a rotating bezel. This system allowed pilots to track a second time zone (such as GMT) in addition to their local time. Like other 10xx series movements, it featured Rolex’s efficient bi-directional automatic winding system and a Breguet overcoil hairspring for stability. The 1066 was produced for a short period, eventually being replaced by the 15xx series around 1959, but its role in launching one of the world’s most iconic travel watches gives it a significant place in horological history.