Heuer began offering the Time of Day Clock and Twelve-Hour Timer, mounted together on a double back-plate, when it introduced the Autavia, in 1933. At that time, the Time of Day Clock was called the "Hervue Junior", and the pair was called the "Hervue". In the late 1950's, Heuer began to refer to the Master Time clock and Monte Carlo stopwatch as the "Rally-Master" pair. Heuer sold the Rally-Master pair, as such, in a larger box that accomodated the double back-plate; over the years, retailers and users have also created their own Rally-Master pairs by taking a Master Time and Monte Carlo and mounting them together on a double back-plate.
For information about the relative values of the Rally-Master pairs, go to Rally-Master Pair in our Values page.