Hydrofarm Autopilot Desktop CO2 Monitor & Data Logger CO2/RH/Temperature monitor on a clear display Trend Chart: shows variable Min/Hr/Day/Wk for readings of CO2/RH/Temperature 2-Channel Low Drift NDIR (non-dispersive infrared) Gas Sensor Audible alarm for low/high CO2 levels Replenish CO2 Reminder: calculates time frame based on usage from past 5 days