The Triplett Model EPC175 Indoor Air Quality Meter displays Particle Count (PM2.5/PM10), Air Temperature, Relative Humidity, Formaldehyde (HCHO) and TVOCs on the 3" Color TFT display with 5 brightness levels. Internal memory stores 5000 data sets (PM2.5, PM10, date and time) and can be displayed as historical data curves. A PM2.5 programmable alarm provides 5 settings (10, 35, 75, 150, 200ppm) to alert you when the selected level has been exceeded. Additional features include programmable auto power off/auto sleep with disable and an auto sleep funtion that turns off the display but measurement still continues. Includes (1) Li-ion battery, AC Adapter and USB power/charging cable.