This item has been discontinued. It has been replaced by the Harvest-Master Climate Pro Controller. Controls night and day length, temperature and humidity control, plus control up to 8 devices (or 7 and a cycle timer), for a balanced climate. All models come as a complete kit. The kit includes: controller, sensors, remote relay switches. Sensors are high accuracy types, for temperature, humidity and CO2. 3 remote relay switches are included for lights and heaters to put on different electrical circuits.