Sound & Flash alarm,MCU processing,Auto-check sensor failure Major Technical Parameters Principle of Sensing deviceCatalytic combustionTarget gasCOAlarm responseRed light flashing and alarm tweetAlarm level50ppm: 60mins -90mins100ppm :10mins-40mins 300ppm : <3minsTemperature range-40°C~+70°CHumidity range30-90%RHWarm-up time after bootImmediateValidity period6 yearsContinuous alarm working time ...