Developed by Sienar Fleet Systems for the Empire, the Imperial XX-23 S-Thread Tracer was made specifically to track ships through hyperspace to destination. It was housed in a missle-like shell, allowing the XX-23 S-Thread to be fired at craft from long distances or during chases. The Inquisitor's TIE Advanced fighter was outfitted with the technology, which he used to tag the Ghost starship.