The ESM3 Eco climate sensor is designed for Growlink controllers that support SDI-12. This sensor includes air temperature, humidity, VPD and photocell with optional CO2. Support for multiple sensors give you the ability to be averaged or used as seperate sensors. Professional growers can rely on this sensor for accurate data and confidence in their growing environment. *Compatible with Precision Irrigation (Bluetooth) Controller, Connect Controller, and any SDI-12 data logger.