Harvest-Master Pro Climate Controller 

The Harvest-Master Pro Climate Controller does everything the climate controller does plus monitors and controls the feeding of CO2 in your grow room for intense flavours and maximum flower/fruit creation. 

Harvest-Master Pro Climate Controller provides automated climate control, CO2 dispensing and day length control, you can have you harvesting bigger, lusher and healthier crops, more often than ever before.

Pro Climate Controller is extremely advanced - there is nothing else like it on the market. The scientist-developed factory settings make growing plants simple and take the guesswork out of growing your plants!

Just set the Growth Cycle you want: Vegetative, Fast Flowering or Full Flowering. This climate controller knows what it takes to achieve the optimum results.

Along with temperature and humidity sensors, there are 8 additional outputs (each needs relay switch) to control Lights, Exhaust fans, CO2, Cooling/Air Conditioner, Heating, Humidifier or Dehumidifier, etc.

More info from the Manufacturer (PDF format - Lots of detail.)