How much gas is left in my cylinder? How long will it last? Truma has the answer to every camper’s question: Truma LevelControl determines the gas level precisely and conveniently via the Truma App. Customers get a detailed overview of their gas supply – more accurately than ever before. The App not only shows the filling level as a percentage and the amount of gas in kilograms, it also tells the user how long the gas will last.