2.8 inch color liquid crystal display (LCD), 320 * 240 pixels. User-adjustable O3 alarm threshold to alert user of elevated levels. It can be used in office, indoor, outdoor, and detection of Ozone residue after disinfection. Large lithium battery with 2000mAh capacity. On-board fan to suck in the surrounding air for more accurate real-time results. Our products are made with the highest quality materials and are designed to provide you with the best possible user experience. We strive to ship out all orders within three days of purchase, and the estimated delivery time is 8-15 days. When shopping, please pay attention to the size and dimensions of the product to ensure that it meets your needs. We are here to help and will do our best to assist you.Thank you for choosing our product. We hope you enjoy it