This part is a kind of semiconductor called MQ-2.

Function of this product has Gas Sensor.

Manufacturers : Hanwei

Image and pinout :

Some of the text within the PDF file :

HANWEI ELETRONICS CO.,LTD MQ-2 http://www.hwsensor.com TECHNICAL DATA MQ-2 GAS SENSOR FEATURES Wide detecting scope Fast response and High sensitivity Stable and long life Simple drive circuit APPLICATION They are used in gas leakage detecting equipments in family and industry, are suitable for detecting of LPG, i-butane, propane, methane ,alcohol, Hydrogen, smoke. SPECIFICATIONS A. Standard work condition Symbol Vc VH RL RH PH Symbol Tao Tas RH O2 Parameter name Circuit voltage Heating voltage Load resistance Heater resistance Heating consumption Technical condition 5V±0.1 5V±0.1 can adjust 33Ω±5% less than 800mw Technical condition -20℃-50℃ -20℃-70℃ less than 95%Rh 21%(standard condition)Oxygen concentration can affect sensitivity Technical paramete [ ... ]

MQ-2 PDF Datasheet Download