Feature: 1. TVOC Sensor: The CO2 detector with TVOC sensor is designed to detector the CO2 value, temperature and humidity of air quality to maintain your healthy environment. It is strongly recommended to use USB for charging. 2. Real Time Detector: The carbon dioxide detector can detect the concentration of carbon dioxide in the air in real time, and four warning lights flash at the same time when it is above 1999. 3. Easy Reading: The CO2 detector uses an intelligent color display with clear numbers. When the CO2 concentration is 1600‑1999, the red warning light starts to flash and alarm. 4. Broad Utility: Portable carbon dioxide detector, compact design, suitable for air quality monitoring in homes, schools, office buildings, hospitals, restaurants, shopping malls, factories, hotels, laboratories and other places. 5. Ideal Present: The great gift for him or her. With the air quality detector, you can definitely understand your environment and improve it according to the actual situation. Specification: Item Type: CO2 Detector Product Material: ABS Carbon Dioxide Detection Range: 400-5000ppm. Accuracy: 1ppm. Temperature Measurement Range: 0-40 ℃. Accuracy: ± 1 ℃. Humidity Measurement Range: 10% - 90% RH. Accuracy: ± 2% RH. Battery: Built in lithium ion battery with 1200mAh capacity. Charging Voltage: DC 5V Charging Time: about 2.5H Normal Use Time: about 6H. Package List: 1 x CO2 Detector1 x Charging Cable (Random Color)1 x User Manual Note: 120 seconds before starting the product is the warm‑up time of the sensor, which can be used only after waiting. If the warm‑up is still inaccurate, it needs to be corrected as follows: 1. Turn on the machine and keep it in ventilated outdoor clean air for 120 seconds or more 2. Double click the button, hear a drip sound, complete the correction.