1. Professional Sensor Adopts NDIR carbon dioxide sensor, needs 1.5s to reflect to sample air, professionally the and professionalism for detecting needs. 3 expression icons display air quality from healthy to unhealthy to notify you window opening and ventilation, ensuring you always live in comfortable environment. 3. Simple & Fast Setup. No complicated app or Wi-Fi required. The alarm threshold can be adjusted between 800 and 2000ppm by double clicking ;M;. If the CO2 concentration exceeds the set alarm value (default setting is 1000ppm), an alarm be issued immediately. 2. Portable Air Quality Monition. This smart air quality monitor measures 3 key air quality indexes: carbon dioxide, temperature and humidity. Real-time data monitoring shows the quality of environment, convenient to use. After receiving the goods, please fully charge the device first. 4. USB Rechargeable Battery. This carbon dioxide monitor has a built-in 1600mAh lithium battery as a backup power source (after the battery is fully , the battery life is up to 24 hours) and comes with a USB charging cable. It is recommended to connect to the power supply for long-term testing., Weight: 0.69666074792 pounds, Manufacturer: Prterver