Aware of the poison from Vistulan food discs, William "Buck" Rogers and Wilma Deering are given these wrist devices prior to their departure to Vistula. Dr. Elias Huer informs them of their use, noting that it will notify them not only to contamination entering their systems but also the dual function of acting like radio directional finders. The finder function works over long distances, allowing Rogers to track Deering into the Sea of Stone after Deering's abduction by Julio from the Governor's Statehouse.
- During their trek through the Sea of Stone, Rogers informs Maj. Duke Danton that the devices are powered by body heat, allowing Rogers to infer that Deering is still alive. However, this information was not part of their briefing in the flight hangar, thus suggesting that he had been made aware of this fact en route to Vistula.