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. 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. 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. 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: NONDK