O3 DETECTOR: User adjustable O3 alarm threshold, which will sound when the threshold is reached to alert the user of elevated concentrations. 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. CLEAR SCREEN: O3 detector adopts color LCD, high definition pixels, easy to view. 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. 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., Manufacturer: YFDGD