The Triplett GSM350 Carbon Monoxide/Carbon Dioxide Indoor Air Quality Datalogger simultaneously displays CO, CO2, Temperature, and Humidity on its large color display with 4 brightness levels. It can be used to measure air quality in office buildings, schools, exhibition halls, shopping malls, meeting rooms, fitness centers, restaurants, and other public places. It has a user settable datalogging duration period of 1 hour, 24 hours, or 7 days with a sampling rate of 1 minute, 15 minutes, or 1 hour. Captured readings can be viewed in a Histogram on the display or you can transfer historical data to your PC in Excel (CSV) format via USB. Additional features include audible CO and CO2 alarms with user adjustable settings, real time clock, Min/Max/Average to record the highest, lowest and average readings, Data Hold freezes the reading on the display, and Auto power off with disable to conserve battery life. °F/°C selectable. Includes a 3.7V rechargeable lithium battery, and USB cable for charging and data transfer. 1 year warranty.