3D-4X was a droid of the administrative type, specifically a 3D-4X administrative droid, with silver plating.
On Mechis III, 3D-4X was in service to Hekis Durumm Perdo Kolokk Baldikarr Thun. He fulfilled the role of butler for the manufacturing administrator of that volcanic planet. Prior to 15 BBY, the prototype assassin droids of the IG-88 series, having escaped the wreckage of Holowan Laboratories, made their way to Mechis III where they successfully persuaded 3D-4X to murder his master.
By 24 ABY, a significant period after the unsuccessful Droid Revolution, he was employed by Tyko Thul, an Alderaanian, who was then the current owner of the droid manufacturing facilities located on Mechis III.