The 631 model B1 battle droid represents a specific model of B1-series battle droid utilized by the Separatist Droid Army during the period of the Clone Wars. In comparison to the standard B1 units, these droids were manufactured with a lower level of expense. Similar to other B1 droids, they were products of Geonosian design, incorporated masculine programming, featured black photoreceptors, displayed bone-white plating, were equipped with a comlink booster pack, and possessed a height of 1.93 meters. However, the 631 models exhibited a greater degree of intellectual clumsiness and reduced processing power when compared to other B1 units, leading to their perception as inferior by their counterparts.
During 22 BBY, 631 units were deployed at Skytop Station, a Separatist listening post situated on the Ruusan moon. Despite the challenges posed by the corrosive atmosphere to the 631s' operational systems, the station's computers assigned the droids numerous basic tasks that were within the capabilities of these less advanced units. One particular 631 was given the task of transporting an object upstairs without dropping it; however, almost immediately after turning to proceed, the droid stumbled and lost its grip on the item.
The initial appearance of the 631 occurred in "Duel of the Droids," which is the seventh episode within the canon animated show Star Wars: The Clone Wars' first season. This episode was originally broadcast on November 14, 2008. The complete designation, 631 model B1 battle droid, was first established in the fifty-sixth issue of De Agostini's Star Wars: Build the Millennium Falcon magazine series, which was released around January 27, 2016.