The Total Survival Suit (TSS) was a mobile combat and protective armour used by human colonial expeditions. It had directed beam weapons and was controlled by a direct link with the operator's brain. It was also capable of functioning autonomously with a simple program (such as "Return to base"). The expedition to Deva Loka was outfitted with one Total Survival Suit.
The suit had been used previously by a member of the expedition called Roberts, but was empty when first discovered by the Fifth Doctor and Adric.
Sanders used the suit when he left the expedition's dome to explore the area. Later, Adric used the TSS to defend against the Mara-possessed Aris' attack, but was unable to control it effectively and his fear made its weaponry activate. The suit fired upon the Kinda and they fled. (TV: Kinda)
Adric received a telling-off from the Doctor shortly afterwards for being so reckless with the TSS, as the entire Kinda tribe could have been wiped out as a result. (TV: The Visitation)