The R7-series astromech droid was an astromech droid manufactured by Industrial Automaton during the time of the Galactic Civil War. This particular R7-series was engineered with the specific intention of being utilized alongside the Rebel Alliance/New Republic E-wing escort starfighter.
The development of the R7-series was kept a secret within the corporation, hidden amidst the publicity surrounding the production of the R6-series astromech droid. The R7 unit was constructed with a third retractable leg, in addition to two permanently fixed wheeled legs, and it also possessed significant shielding to protect it from electrical surges. The primary role of these droids was on E-wing starfighters, and they needed considerable alterations to properly function with X-wing or Y-wing starfighters. A standard R7 unit had the capacity to store up to fifteen hyperspace jump coordinates within its astrogation buffer and could withstand a near impact from an ion cannon.
A duplicated version of the R7's advanced droid brain was implemented in the Imperial XR-85 tank droid.
The R7-A7 astromech droid featured in the The Clone Wars series has been classified as an R7-series droid. The Clone Wars Character Encyclopedia does confirm that R7-A7 is a prototype droid, but it is not stated if the droid is a prototype of the R7 model made after the Battle of Endor.
R7-D4 is known by the nickname "R7," but he was made before the R7 was released. However, the initial pair of characters in a droid's designation do not always indicate the model series, because they are part of a longer name, so this may not be a continuity error.