Solar Sync is a sensor system that, when connected to a Hunter controller, will automatically adjust your controller watering based upon changes in local climate conditions. The Solar-Sync utilizes a solar and temperature sensor to measure on-site weather conditions used to determine evapotranspiration (ET), or the rate at which plants and turf use water. In addition, the Solar-Sync sensor includes a Hunter Rain-Clik and Freeze-Clik sensor that will shut down your irrigation system when it rains and/or during freezing conditions. A small module connects the sensor to the controller and will automatically increase or decrease watering run times based on changes in weather.