Widely used in homes, offices, businesses, government facilities, schools, and other environments to monitor indoor air quality. Clear and informative display: a 2.8inch LCD screen directly shows each air data, along with average values, realtime values, and environmental suggestions for assessing air quality at a glance. Easy to read and proactive alerts: simple, legible numbers with an audible alarm to indicate when the air is unsafe. Portable power with practical runtime: builtin 1200 mA rechargeable battery. When powered via USB, standby time ranges from 4 to 6 hours. Comprehensive air quality detection: the device uses a builtin electrochemical sensor to accurately detect carbon dioxide (CO2), formaldehyde (HCHO), volatile compounds (TVOC), and particulate matter (PM2.5/PM10) in the air. Practical advantages: combines realtime data, average values, and actionable environmental suggestions in one display, with an audible alert to help you respond quickly. Use scenarios: In the home: monitor living rooms or bedrooms to ensure comfortable and safe indoor air for family members. In offices or classrooms: track CO2 levels to manage ventilation and maintain a productive, healthy environment. In government buildings, schools, and commercial spaces: regularly assess air quality in common areas and meeting rooms to support occupant safety and compliance.