A tuning stylus was a device used by roboticists for adjusting droid machinery.
After the droid informant 8t88 lost an arm on the moon Nar Shaddaa during the year 5 ABY, he retreated to the Government House on the moon Sulon for business related to the Imperial Remnant. An arm was transported to him from a fellow Model 88-series administration droid, but lacking a qualified roboticist, he had to attach it to his own body. 8t88 asked his bodyguard Rol to hand him a tuning stylus from an array of tools laid before him, but Rol instead picked a testing probe, as he could not tell the difference between the two tools. 8t88 angrily discarded the testing probe and used the tuning stylus to finish his job with.