MQ2 MODULE This analog gas sensor has a small heating element with an electronic-chemical sensor. It is suitable for use

MQ-4 Methane Sensor The sensitive material of the MQ-4 gas sensor is SnO2, which with lower conductivity in clean air.

MQ-8 gas sensor is suitable for sensing is Hydrogen Gas which with lower conductivity in clean air. When hydrogen gas

Air quality sensor for detecting a wide range of gases, including NH3, NOx, alcohol, benzene, smoke and CO2.Ideal for use