... use FEATURESHC, CO, CO2 are measured by NDIR method and O2, NO are measured by electrochemistry method. Highaccuracy, with automatic compensation ... engine rotating speed (optional).FG-410(4G): HC, CO, CO2, O2, y , oil temp (optional), engine rotating speed (optional).FG-410 ... (5G): HC, CO, CO2, O2, NO, y , oil temp (optional), engine rotating speed (optional). ...