The Lascar EL-USB-CO300 data logger measures and stores up to 32,510 Carbon Monoxide (CO) readings over a 0 to 300 ppm measurement range and -10 to 40 C (14 to 104 F) operating temperature range. The user can easily set up the logging rate and start time, and download the stored data by plugging the data logger into a PC's USB port and running the purpose designed software under Windows 98, 2000, XP, Vista & 7. The data can then be graphed, printed and exported to other applications. The data logger is supplied complete with a long-life lithium battery. Data is stored in non-volatile memory and is not lost when the battery is empty. A bright red LED will flash and a buzzer can sound when a preset warning level has been exceeded. IMPORTANT SAFETY WARNING ELUSBCO300 is a professional instrument that is designed to measure and record levels of Carbon Monoxide (CO) in air over a period of time. It takes a sample reading at set intervals for recording / monitoring / analysis purposes. It is not a suitable substitute for a domestic or industrial Carbon Monoxide detector/alarm.