... themselves, prevent from wrong alarm, exterminate missing alarm , be more reliable Main Function 1.Adopt patent gas detector, lower ... design to induct coal gas, natural gas and petroleum gas.3.Intelligent control, check by themselves, prevent from wrong alarm, exterminate missing ... .5.Easy installation Specification 1. Kinds of gas: coal gas, natural gas and petroleum gas 2. Alarm density: 0.1% to ...