Trangia gas burner runs on gas cartridges with Propane/Butane/Isobutane mixture. The valve is international standard: EN417 threaded valves (7/16 NS Lindal Valve).
These cartridges are available in most countries around the world. There are many different brands of cartridges available on the market. Gas canisters are normally available in 3 different sizes 100 g, 230 g and 450 gram. For cold temperatures we recommend Primus Winter Gas, it works effectively down to -22°C.
The Quality of the cartridge and gas may vary. Well known brands of high-quality gas cartridges are: Primus, MSR, Optimus & Jet boil. In Sweden you buy gas at most outdoor shops, petrol stations, grocery stores and hardware stores such as Jula, Biltema, ÖoB, and Claes Ohlson.
Examples of gas cartridges and valve: