ET Manager uses real-time weather conditions to ensure that landscapes are kept at an optimum moisture balance. Offers users significantsavings, deeper root systems, and a healthier landscape. Works with virtually any irrigation controller and irrigation configuration. Rather than relying on time-based scheduling system, the ET Manager uses real-time weather conditions to calculate the evapotranspiration (ET) rate. Allows existing controller to irrigate precise amounts of water only when the soil moisture balance reaches user-set levels. ET is the amount of water lost from the soil (evaporation) plus plant water loss (transpiration).