... FEATURESHC, CO, CO2 are measured by NDIR method and O2, NO are measured by electrochemistry method. Highaccuracy, with ... 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 ... 12ppm vol (absolute error) or { 5% (relative error) Gas analyzer