Engineer droids were distinguished by the orange markings on their head and shoulders. Their advanced programming allowed for the operation of virtually every vehicle-allied or otherwise in existence. They were also effective at repairing damaged vehicles as well as slicing into enemy vehicles for capture or sabotage.
They would usually engage their targets from close range. Their armament included an shotgun, detonation packs, and a F-187 fusioncutter. Because of the versatility of their arsenals they were valuable assets to the CIS on any battlefield.
Engineer droids droids were deployed during many battles of the Clone Wars, such as the Battle of Geonosis, the Battle of Mygeeto, the Battle of Felucia, the Battle of Kashyyyk and the Battle of Utapau.
Following the end of the Clone Wars, they saw action on Mustafar with Gizor Dellso's Separatist holdouts.
Engineer droids first appeared in the 2005 video game Star Wars: Battlefront II. They replaced the droid pilot playable in Star Wars: Battlefront as the new CIS engineer class.