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. About Shipping: All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances.Any questions, please feel free to contact us During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours, wish you a happy shopping Thanks for your cooperation and we'll make you feel satisfied.