Features:  2.8' color liquid crystal display (LCD), 320 * 240 pixels.  User adjustable alarm threshold for O₃ to alert user of elevated levels.  It can be used in office, indoor outdoor and detection of ozone residue after disinfection.  Large 2000mAh capacity lithium battery.  On-board fan to draw in ambient air for more accurate real-time results.  Micro USB charge Low battery warning.  Electrochemistry sensor for O₃. Temperature and Humidity sensor. AQI for ozone concentration index. Support time and date, self-calibration function.  LCD screen, display various parameters.  USB charge port for convenient using.  With a storage box for easy carrying.     Specifications:  Material: ABS;  Color: black+orange;  Screen size: 2.8in;  O₃ concentration AQI:  0~0.100: Fine;  0.100~0.300: Slight;  0.300~1.000: Moderate;  1.000~4.999: Serious;  Battery: 1 * lithium battery, 2000mAh (included);  Item size: 164 * 74 * 26mm / 6.5 * 2.9 * 1.0in;  Package size: 280 * 225 * 70mm / 11.0 * 8.9 * 2.8in;  Package weight: 501g / 1.1lb.     Package includes:  1 * Air Quality Monitor;  1 * USB Cable;  1 * User Manual;  1 * Box.