Figaro tgs 3870 combination methane and carbon monoxide gas sensor figaro tgs 3870 a small bead mos type combination sensor that is designed to detect both methane and carbon monoxide the miniature size of the sensor together with cyclic heater operation enable the sensor to have a highly selective detection profile and low power consumption the sensor suitable for applications where a combination of methane and co sensor are required figaro tgs 3870 combination gas sensor