The BHC-1a Basic Humidity Controller is designed to control fans, dehumidifier, humidifiers, misters and other ventilation equipment in gardens, greenhouses, grow rooms or other environments. The BHC-1a can operate in either dehumidification or humidification modes. The BHC-1a features a readily visible switch to alternate between dehumidify and humidify settings. The easy to read dials make programming daytime and nighttime settings uncomplicated. The (3) function LEDs let users know if the controller has main power, if the controller is in operation, as well as whether the controller is sensing day or night.