R4 - series agromech droid Flushed with the success of their landmark R2 launch , Industrial Automaton rushed to capitalize on their new dominance of the astromech droid market . The R4 - series agromech droid was a highly successful attempt to capture a new market prospect — the Outer Rim urbanite who was more likely to have a souped - up landspeeder parked in their garage than an X - wing . Accordingly , the R4 agromech droid was designed for life outside the pristine hangar bay . It was simpler , tougher , and cheaper than previous R3 - series models . Characteristics . The R4 had the same outward appearance of an R2 or R3 droid below the neck , but to save money on production , items such as the video display screen and miniature fire extinguisher were omitted . The holographic projector / recorder unit was retained , but relocated to the top of the head dome to allow for use of a cheaper , less miniaturized unit with a smaller rotational axis . The droid ' s Intellex VI computer was advanced , but geared toward common repulsorcraft designs and specs for commercially available space transports . The computer brain was designed with more space between the components , lowering production costs , but requiring a larger head dome , and likewise eliminated many of the function indicators and gadgetry found on other R - series head domes . The R4 was unsuited to the task of starfighter astromech ; it could only hold the coordinates for a single hyperspace jump in its astrogation buffer , a one way trip for any fighter jock . The droids were rugged ; able to shrug off the nicks and dents common to a working garage environment as well or better than other R - droids . IA was pleased to discover that , with regular maintenance checks , the R4 outlasted its design parameters for operational life , weather endurance , personality matrix stability , and time elapsed between recharge sessions . Because of their increased durability , R4s were the preferred " mech " droids used by the Jedi . Given the interstellar nature of their work , however , most of the R4 droids purchased for the Jedi were modified to include the more expensive R2 style head . This gave them many of the best features of the R2 and R4 series . Many of these droids were further modified by mechanics in the Jedi Temple to permanently interface with the Delta - 7 " Aethersprite " - class light interceptor , until the Jedi moved on to the Delta - 7B and Eta - 2 " Actis " - class interceptor . Even so , pilots retained R4 units in the Eta - 2 interceptor . History . Mass - market buyers liked the R4 , as did the freedom fighters of the Alliance to Restore the Republic . They reasoned that no one would be suspicious of a mass purchase of agromech droids , the way they would be of starfighter - ready copilots like the R2 . The model ' s low cost and knowledge of general - purpose vehicles were also greatly appreciated by the resource - strapped Rebels , and soon the droids ' conical heads were familiar sights in Alliance bases and Mon Calamari hangar bays . A few R4s , equipped with non - standard magnetic fault sensors , were used by the Galactic Empire to detect flaws and weaknesses in the atmospheric containment fields in hangar bays on board both Death Stars and on Star Destroyers .