PDF Data Export Function -- 2000 goups value records, display the MAX, MIN and AVG values of carbon dioxide, temperature and humidity. Export PDF function allows you to connect with computer and export the PDF file for conveniently checking and analyzing. 4 Inch TFT Full Color Display -- Large screen real-time display current time, date, CO2(MAX, MIN and Emoji Grade), temperature, relative humidity, data record interval and recordings and battery power. Display backlight brightness, standby time and RGB indicator light are adjustable. Alarm Setting -- Real time CO2 monitoring by the high precision sensor, and it will alarm you once the CO2 is exceed the setting value. The buzzer alarm can turn off according to your demands. 2200mAh USB Rechargeable -- 2200mAh large battery capacity, 3 hours full charging and support over 10 hours working demands. USB charging port can be powered via almost any standard USB port, e.g. power bank, laptop or adapter.