Desktop 3 in 1 Carbon Dioxide/Relative Humidity/Temperature Meter, CO2 ppm RH C/F Indoor Air Quality Monitor, for Home Grow Growing Room Continuous Monitoring Clock with Date & Time CONTINUOUS MONITORING- 15-degree tilted angle designed for easier to see and read on desktop; Powered by 5V power adapter (Included). Ideal for long term continuous monitoring. AIR QUALITY LEVEL INDICATOR- This CO2 meter does not only tell the measurement in digit, its display can also tell if the air quality level is at GOOD, NORMAL or POOR Level. No more guessing or searching on the internet. Default setting: Good= 1000ppm. Users can change this indicator setting. MULTIPLE MEASUREMENTS ON LARGE & CLEAR DISPLAY- CO2, Temperature, Relative Humidity, Air Quality Indicator, Date and Time are displayed on the big LCD display at the same time. AUDIBLE CO2 ALARM- Audible alarm will beep when the CO2 level exceeds the preset value (Default setting is &gt;1000ppm). This alarm threshold can be adjusted according to users needs. Alarm can be paused. HIGH ACCURACY & NDIR SENSOR for CO2 DETECTION- Non-dispersive infrared technology is used to ensure the reliability and long-term stability. This meter measures 0~9999ppm, while it can maintain a high accuracy at +/- 50ppm in the range of 0~2000ppm, provides reliable readings for daily use.