Feature: 1. High Accuracy and Sensitivity: This CO2 detector has a high accuracy and clear display screen, with a CO2 range of 400‑5000ppm, temperature range of ‑10℃ to 50℃, and humidity range of 20%‑85%RH, providing convenience for your life. 2. Real Time Monitoring: Sampling at 1.5 seconds per time, this CO2 tester will alert you with an alarm sound when the PPM value increases, and supports turning off the alarm. You can calibrate the CO2 tester to ensure its accuracy over time. 3. Rechargeable Battery: This CO2 detector has a built in 800mAh large capacity lithium battery, which is convenient for long term use. Equipped with charging interface and USB charging cable, and can be charged for 2 hours to ensure 24‑hour use. 4. User Friendly Design: This desktop CO2 detector is designed with support legs to provide a stable and reliable structure. Support display brightness adjustment for use in different lighting conditions and effectively care your eyes. 5. Portable and Practical: This digital CO2 detector features a compact size and lightweight design, making it convenient to use and carry. It is suitable for home, office, classroom, travel or outdoor use, meeting your more needs. Specification: Item Type: Desktop CO2 Detector CO2 Detection Range: 400-5000ppm Temperature Detection Range: -10℃ to 50℃ Humidity Detection Range: 20%-85%RH Sampling Time: 1.5 Seconds Battery: 1 x 800mAh Rechargeable Lithium Battery (built in). Package List: 1 x CO2 Detector 1 x User Manual 1 x USB Cable