1.28inch color LCD display with 320x240 pixels provides clear, real time ozone readings for easy monitoring. User adjustable O3 alarm threshold allows you to set the alert level to match safety requirements and be alerted when ozone concentrations rise. Wide range of applications for detecting ozone residuals in offices and other indoor spaces, indoors and outdoors, and after disinfection. 2000 mAh capacity lithium battery supports USB charging and includes a low battery warning to help you plan recharges. An onboard fan draws ambient air through the sensor for more accurate real time results. Use scenarios After disinfection in an office or work area, verify that ozone residuals are within safe limits before reoccupying the space. Monitor ozone levels in indoor spaces such as classrooms, clinics, retail spaces, or other facilities during and after ozone based treatments or air purification processes. Assess ambient ozone exposure at outdoor entry points or work sites where ozone levels can vary, helping to protect occupants and workers.