Features: Application: suitable to use at home, office, in the car, outdoor and other environmental testing. Temperature/humidity meter: The PM2.5 detector meter also can measure indoor/outdoor temperature and humidity. Alarm function: when the detected result over the setting value, the result will blink in red to alarm. (alarm setting: short press SET to set he alarm, display shows the current alarm value.) Accurate to detect PM2.5 in air with advanced detection sensor technology in real time. This LED PM2.5 detector built-in large capacity battery, long standby time. Continuous work over 4.5 hours with USB cable charging function. Easy to carry with the super mini pocket size and light weight - monitor air quality wherever you are. Auto power off: it cannot be power off automatically 30 minutes without any operation. Digital LED display screen shows the testing results, easy and clear to read. Package Included: 1 x SW-825 PM2.5 Detector Meter 1 x USB Cable Application: suitable to use at home, office, in the car, outdoor and other environmental testing. Temperature/humidity meter: The PM2.5 detector meter also can measure indoor/outdoor temperature and humidity. Alarm function: when the detected result over the setting value, the result will blink in red to alarm. (alarm setting: short press SET to set he alarm, display shows the current alarm value.) Accurate to detect PM2.5 in air with advanced detection sensor technology in real time. This LED PM2.5 detector built-in large capacity battery, long standby time. Continuous work over 4.5 hours with USB cable charging function.