MST 420P portable gas detector can be used in: rapid detection of a variety of gas concentration and measurement of environmental temperature and humidity, if the measurement exceeded the limit value, the alarm will emit sound & light vibration as alarm. MST 420P adopted 2.31-inch high-definition color screen for real-time display, adopted the gas sensors of industrially well-known brands, and the main detection principles include: electrochemical, infrared, catalytic combustion, thermal conductivity, PID photoionization, and so on. Advanced electric circuit design, mature kernel algorithm processing, unique external appearance design, had achieved a number of patents about the software works, external appearance, and so on. MST 420P is suitable for detecting the concentrations of gases in the atmosphere environment in the pipeline or confined space; and the purity of the gas leakage and various high concentration single gases with the background gas as nitrogen gas or oxygen gas. The types of gases for detection are more than 500 types.