According to the national regulations, the carbon monoxide alarm needs to be tested once a year, so that the carbon monoxide gas leakage can be detected quickly, accurately and stably, so as to realize the safety protection of the carbon monoxide environment in a real sense and improve the safety of the on-site operators. Since the carbon monoxide sensor, the core component of the carbon monoxide alarm, needs to be calibrated once a year, the main purpose of this is to improve its sensitivity, accuracy and stability of detecting carbon monoxide, and some manufacturers will charge a certain fee for calibrating the carbon monoxide alarm, mainly the labor cost, the cost of raw materials used and the response calibration technology provided.