Fourth class (class 4) droids, also known as fourth-degree droids, were droids skilled in security and military functions. Fourth-degree models included the B2 super battle droid and the KX-series security droid. Most fourth class droids were not programmed to speak and interact with organic beings. The KX-series was an exception, though was not proficient at it when compared with a protocol droid.
- Star Wars Propaganda: A History of Persuasive Art in the Galaxy
- Star Wars: Rogue One: Rebel Dossier
- Star Wars: The Visual Encyclopedia (First identified as fourth-class droid)
- Star Wars: Droidography