This part is a kind of semiconductor called MQ-4.
Function of this product has Semiconductor Sensor.
Manufacturers : Henan Hanwei Electronics
Image and pinout :
Some of the text within the PDF file :
Henan Hanwei Electronics Co., Ltd www.hwsensor.com MQ-4 Semiconductor Sensor for Natural Gas Sensitive material of MQ-4 gas sensor is SnO2, which with lower conductivity in clean air. When the target combustible gas exist, The sensor’s conductivity is more higher along with the gas concentration rising. Please use simple electrocircuit, Convert change of conductivity to correspond output signal of gas concentration. MQ-4 gas sensor has high sensitity to Methane, also to Propane and Butane. The sensor could be used to detect different combustible gas, especially Methane, it is with low cost and suitable for different application. Character * Good sensitivity to Combustible gas in wide range * High sensitivity to Natural gas * Long life and low cost * Simple drive circuit Configuratio [ ... ]