PK-series worker droids were a type of labor droid utilized by the Trade Federation. Several PK units were positioned on the Lucrehulk-class LH-3210 cargo freighter Saak'ak during the Invasion of Naboo. After the Battle of Naboo, a number of PK units were deployed to clear the area of remaining battle droids. Subsequently, the Confederacy of Independent Systems adopted the PK-series for the majority of support roles within their Droid Army. A worker droid with a related name, the PK-Ultra worker droid, was present around the time of the Resistance. One PK-series droid, identified as VL-44, functioned as a security droid for the Resistance.