Heuer introduced its revolutionary Chronosplit chronograph in 1975. The first version of the Chronosplit (Reference 100.703) featured an LCD display for the time-of-day and an LED display for the chronograph functions. The LED (chronograph) proved to be problematic in several respects, including the battery consumption required to power the red display and problems with the LED multiplexing. Becuase so many of these early Chronosplits were returned to Heuer for repair, Heuer quickly changed the design to incorporate a second LCD display for the chronograph function. This second version of the Chronosplit was the Reference 102.703.