The product is a new generation of miniature smart detectors that can continuously detect the presence of flammable, explosive flammable gas mixtures in methane concentration. With audible and visual alarm, display voltage, undervoltage alarm, zero point automatic tracking adjustment, easy to use features. JCB4 methane detection alarm applies to the environment or mines with methane or coal dust explosion hazard, and staff to measure the methane content of the instrument. The instrument uses microprocessor technology, all calibration parameters and the linear correction is done by software, with small size, light weight, simple operation, easy maintenance, etc.