B3 battle droids were a type of battle droid produced by Baktoid Combat Automata and utilized by the Confederacy of Independent Systems throughout the Clone Wars. The B2-series super battle droids, along with B3 battle droids, were preferred over the costly and intricate E522 assassin droids. There was at least one B3 unit that was positioned in proximity to a listening station situated on the planet Vanqor. A section of curved metal, used for fixing B3 droids, was discovered by Quinlan Vos during his and a Republic assault team's attack on that listening post.
Furthermore, Temmin Wexley came across components of a B3 while attempting to infiltrate the Satrap's Palace located on Akiva.