☢Made of it is and good performance , long service life ☢It adopts advanced catalytic sensor , quickly response , fast alarm , low consumption and ☢When the concentration of flammable reaches 2 % , yellow LED lights up ; when the reaches 10 % , red LED lights up ☢It can be used to natural methane , biogas , and other flammable ☢ Pen shape , compact size , easy to carry, Manufacturer: Watreketal