Sentinel EVC-1 Environmental Controller 

Temperature, humidity and CO2 are all environmental conditions inside a growing area that need to be controlled for successful gardening. The Sentinel EVC-1 Environmental Controller controls all three and more. It's simple-to-use and reliable, yet affordable. 

This solid-state environmental controller has selectable CO2, temperature, and humidity modes that allow the user to control temperature and humidity separately or control them together. There's a built in photocell to activate CO2 device during the day, plus a night device outlet to control an exhaust fan, sulfur burner, etc.

The EVC-1 controls temperatures by operating a device such as an air-conditioner or exhaust fans. The humidity is separately controlled and can be set to either increase or decrease the humidity to a specific level. It can also coordinate the use of supplemental CO2 with the temperature control function.

The EVC-1 has four receptacles to control up to 15-amps of power, plus a built-in, re-settable circuit breaker.

Specs:

Temperature Mode: Cooling
Min / Max operating temperature: 32 to 120° F
Temperature Accuracy: +/- 2° F
Humidity Mode: Humidify or Dehumidify
Min / Max Humidity: 0-99% RH
Humidity Accuracy: +/- 7% rH
CO2 Mode: Daytime
Thermostat type: Remote bulb 30”
Amps / Volts requirements: 15 amps @ 120 volts
Dimensions: 8" high x 6.5" wide x 3.1" deep
Weight: 7 lbs
Life Expectancy: 10+ years

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