The BDE-2 battle droid was a model of battle droid produced by the Techno Union's Earth Division, "BDE-2" stood for "Battle Droid, Earth, 2nd Model", the BDE-1 battle droid being simply the TUED factory designation for B-1 battle droids produced by it.
The BDE-2 was the first model of battle droid designed and produced specifically by the Techno Union Earth Division, the BDE-2 was an Earth Divsion designed analogue of the B-1 battle droid, and was designed to perform a similar role, the BDE-2 was slightly shorter than their B-1 relatives, however, but also had superior AI and programming, making them more expensive than their cheaper B-1 counterparts, as a result the BDE-2 was rarely seen outside of the Solar System, and was almostly excusively used by Separatist militaries within the Solar System.
As with all of the TUED's droids the BDE-2 was painted in the TUED's default grey factory paint, TUED used grey for their factory paint because the Confederate military wore grey uniforms, however some BDE-2 received camo field paint form units which received, it was far more common for army units to paint their droids than the navy.
During the First, Second and Third battles of Earth the BDE-2 served against the Clone troopers of the Galactic Republic/Galactic Empire, the BDE-2 droids were nicknamed "Wedge-Heads" by the Clones due to the droid's notably wedge-shaped head. The Confederate States of Earth used the BDE-2 for at least 60 years, because some were still in use as late as the Battle of Earth of 40 ABY.