this astromech droid was owned by Lorn Moonrunner, and was used to assist in flying the starship Refugee. R2-4B wore what appeared to be a standard restraining bolt, but Lorn had modified a detonation device to resemble the bolt. This was all a precaution taken in case the Empire should ever discover that Lorn - the former Imperial Major Corvus Langlier - was on Rhamalai. When this finally happened, shortly after the Battle of Yavin, R2-4B was confiscated and placed in the Imperial droid pool. When R2-4B had been placed in the garrison in Argona, it activated the programming which activated the detonator. The resulting explosion destroyed much of the Imperial garrison.