The XX-23 S-thread tracker, also known as the XX-23 homing beacon, functioned as a tracking device that Neuro-Saav Technologies manufactured and employed during the period of the Galactic Civil War; it used s-threads for tracking.
This XX-23 device was compact and cylindrical, continuously emitting a signal receivable by HoloNet s-threads. Using the received signal, a specialized computer could ascertain when a vessel traversed an s-thread, allowing for the plotting of its trajectory.
A molecular bonding agent enabled its attachment to a starship's exterior. The tracker harnessed the vessel's thermal and radiative output as a power source, which complicated detection compared to other tracking methods.
The homing device, placed on the Millennium Falcon by a HMOR homing droid, represented a modified iteration of the XX-23 blueprint.