The SP-4 protocol droid is an older model of droid, first introduced around the time of the Ruusan Reformation approximately one thousand years BCGT. The original manufacturer, Cybot Galactica, intended for the droid to provide analytical assistance to their owners while not threatening the sale of the company’s higher-end models. The SP-4 was designed with more of a budget cost and performance in mind, and as a result, they are less capable than some more modern droids.

The average SP-4 droid stands a shade under a meter and a half tall. In a conscious effort to make the droid appear as friendly as possible, Cybot gave the droid more child-like proportions, with shorter arms and legs and a larger, saucer-shaped head with goggle-shaped photoreceptors that give it a very innocent expression. The company also saved on costs by utilising parts from their existing PK-series worker droid. The resulting unit was quite a success story for the company – even the Jedi Order purchased a significant number of them to help operate the analysis wing of the Jedi Temple on Coruscant.

The models purchased by the Jedi Order were significantly upgraded with sensory apparatus and behavioral circuitry matrices as well as being modified to withstand frequent decontamination in order to avoid polluting the analysis chambers. In the Jedi Archives, the droids would wirelessly link into mainframe data libraries to swiftly evaluate the details of any events that interested the Jedi, including the investigation of crime scenes although the final conclusions were usually left to the Jedi themselves. Despite their limitations, SP-4s remain prized by collectors and frontier curators.