The MIRROR-ANALYSER SF6 uses the physical dew point mirror measuring principle which is characterised by its high precision and utmost reliability in order to measure the moisture content. By cooling the integrated mirror the moisture content of the gas is determined by measuring the temperature depending on the condensation or icing of the mirror. The other parameters of SF6 quality are determined by measuring the speed of sound (SF6 volume percentage) and electrochemical reaction (SO2 concentration).