... methane liquefied flammable gas for Ardu Product DescriptionMQ-2 gas sensor using gas-sensitive materials with lower conductivity in clean air ... the gas concentration using a simple circuit.MQ-2 gas sensor for liquefied petroleum gas, propane, high sensitivity of hydrogen, natural ... :1, using high-quality dual-panel design, with a power indicator and TTL signal output instructions;2, with a the DO ...