Quickly detect the concentration of combustible gas and the measurement of ambient temperature and humidity. If the measurement exceeds the limit, an audible and visual vibration alarm will be issued. Misoperation recognition function: automatic identification and prevention of misoperation of concentration calibration, which can avoid defects caused by human factors Zero point automatic tracking, long-term use is not affected by zero point drift Resistant to high-intensity pulse surge electric shock. With anti-reverse function, Manufacturer: CVFRDD