Feature: 1. O3 DETECTOR: User adjustable O3 alarm threshold, which will sound when the threshold is reached to alert the user of elevated concentrations. 2. USB CHARGING: The O3 detector is equipped with a USB charging port and a high capacity 2000mAh li battery that warns when the battery is running low. 3. CLEAR SCREEN: O3 detector adopts color LCD, high definition pixels, easy to view. 4. ACCURATE READINGS: Built in electrochemical sensors, temperature and humidity sensors, and an on board fan that draws in surrounding air for more accurate real time results. 5. SMALL AND PORTABLE: The small size and light weight of the O3 detector makes it very convenient to carry around so that you can monitor the O3 concentration in the air at any time. Specification: Item Type: O3 Meter Detector Material: ABS Color: White O3 Sensor Technology: Electrochemical Temperature and Humidity Technology: Temperature and humidity sensors O3 Detection Range: 0-50ppm (Accuracy 0.01ppm) Battery: 1 x 2000mAh rechargeable li battery (shipped with built in battery) Display: 3.5in LCD display Atmospheric Pressure: 86Kpa-106Kpa Sampling Time: 1.5sec Detection Temperature: -10℃-50℃ (accuracy ±1℃) Humidity: 20%-85% RH (accuracy ±4% RH) Storage Temperature: -10℃ to 60℃. Package List: 1 x O3 Meter Detector1 x USB Cable1 x Instruction Note: The product vent sensor is on the back of the detector, when you first turn on the detector, you need to let the detector stand up, not lying flat and no obstruction behind. Wait 10 minutes after the detector will be the previous environment of the air convection out, and the values will be calibrated.