After the Yuuzhan Vong War, Tendrando Arms adapted the popular YVH-series battle droid into a personal protection and combat droid for wealthy citizens and government officials. At the outbreak of the Second Galactic Civil War, Tendrando Arms provided newly promoted joint Chief of State Jacen Solo with one of these battle droids to serve as his personal bodyguard. This droid, known as SD-XX was regularly sighted with Solo during his reign in the Galactic Alliance.
The SD-X was slightly smaller than the YVH, and did not have the Yuuzhan Vong features. It also did not have the specialized sensor suite for detecting Yuuzhan Vong infiltrators.
It was covered in a black, non-reflective, sensor-baffling proprietary stealth coating which allowed it to stay undetected. It could be a very effective fighter, but was more commonly used in protection duties.
The SD-X was very determined and focused, and was known to track down assassins and criminals weeks after the attack on the person they were assigned to protect had happened.