R2 series astromech droids, also known as R2 units, were a very popular series of astromech droids produced by Industrial Automaton. They stood at around 1 meter in height, and were programmed to perform a variety of tasks. They were designed to be able to fit in the droid sockets commonly found on starfighters. R2-D2 was a notable example of this model. Although the R2 series was used prior to the Clone Wars, they were still considered to be new during the Age of the Empire. According to C1-10P, a C1-series astromech droid, the greatest flaw in R2 units' programming was compassion.
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