AA-2 Keeper
The AA-2 Keeper was a slave control device designed by Yin Vocta through his company Vector Technologies. The Keeper was actually a combination of a beacon and a tracking unit. The beacon was implanted beneath a slave's skin where it could only be safely removed with the associated tracking unit. This extraction was also password protected to prevent slaves from escaping. The beacon allowed the owner to track his slaves range, speed, and direction up to 25 kilometers away. If the slave moved beyond that range the beacon would release an exotic neurotoxin that would instantly kill the subject.
Behind the scenes
The AA-2 Keeper was designed by Paul Danner and Bill Smith for Wretched Hives of Scum & Villainy, a supplement for the Star Wars Roleplaying Game that was published by West End Games in 1997. In that supplement Kaylo NaKuda had a Keeper implanted into his slave Sil Vaturha.