A Sontaran gas canister was a device which was included in Sontaran space pods.
Commander Kaagh had such a gas canister inside his spacepod. Luke Smith mixed dylixium chloride, korazic acid and lyzirium phosphate to create a knock out gas. He filled the gas into the Sontaran gas canister. The gas would disable a human for two hours and a Sontaran for several minutes. Luke wanted to use the gas on Commander Kaagh. However it was later used on Chrissie Jackson, by Maria and Alan Jackson because they did not want Chrissie to know that aliens existed. Chrissie passed out in the building of the Tycho Project. She woke up at 36 Bannerman Road and was told that all her experiences with Kaagh were just a dream. Chrissie however knew her experiences were real. Sarah Jane Smith later kept the Sontaran gas canister inside her attic at 13 Bannerman Road. (TV: The Last Sontaran)