Factory direct MQ-2 smoke gas sensor module methane liquefied flammable gas ... suitable for liquefied petroleum gas, butane, propane, methane, smoke, etc., the probe can be used in homes and ... voltage.5 of liquefied natural gas, city gas, smoke better sensitivity.6, there are four screw holes for ... the sensor module New Factory direct MQ-2 smoke gas sensor module methane liquefied flammable gas for Ardu ...