Heatspex were a specialized type of goggles designed to allow the person wearing them to perceive heat signatures. To navigate the thick fog in the lower regions of Milvayne, Vulaada Klam utilized a pair of these goggles. Following her encounter with Klam, Chelli Aphra also used a pair of heatspex, having borrowed them.
The inhabitants of the Milvayne underworld employed heatspex as a means to see through the dense fog that was deposited there by bloatbarges. Among these residents was Vulaada Klam, a war refugee who had been relegated to the underworld because of errors in her parent's flawed records. After the criminals Chelli Aphra and 0-0-0 were compelled to descend from the upper city into the underworld, they struck a bargain with Klam for transportation aboard her Qaberworm Gurtyl, and Aphra borrowed a pair of her heatspex. She continued using them until Klam "sold her out" to the Milvayne Authority.
The initial appearance of heatspex occurred in the canon comic Doctor Aphra (2016) 27. The comic was written by Si Spurrier, the illustrations were done by Emilio Laiso, and it was released on December 12, 2018.