A series of extremely robust, easy-to-maintain and powerful portable measuring instruments. The COMBIMASS® GA-m Series represents a milestone in the development of mobile gas analysers. It is excellent for analysing digester gas, sewer gas and also landfill gas from landfills. It has an easy-to-service structure and plug-in system modules so that the instrument can be expanded and upgraded to the latest version at any time. A powerful internal gas pump allows measurements to be taken even in negative-pressure gases and the use of a nickel-metal hydride battery enables the instrument to be used for approximately eight hours without recharging.