Sentinel CPPM-1 CO2 PPM Controller 

Maintaining a CO2 level between 1000 and 1500 PPM is essential for most plants. The CPPM-1 controls your growing area's carbon-dioxide levels with part-per-million (PPM) accuracy. 

The Sentinel CPPM-1 CO2 PPM Controller uses a CO2 sensor that is extremely precise and features a ten-year life expectancy. This remote CO2 and light level sensor can be positioned inside the growing area with the CPPM-1 unit positioned outside of the grow room. It comes with a 16' cord, but can be extended up to 100'.

As you would expect from Sentinel, the LED display on the CPPM-1 is easy to read and provides simple pushbuttons to enter the desired PPM settings and to display the current CO2 PPM reading.

The CPPM-1 can also be connected to other controllers so that the CO2 is disabled (useful when operating exhaust fans), or it can be operated in Fuzzy-logic mode when using compressed CO2, or ON-OFF when using CO2 generators.

CPPM-1 specifications:

Amps / Volts: 15 amps @ 120 volts
Min / Max operating temperature: 32 to 120° F
Min / Max operating humidity: 0-99% RH
Light Sensor sensitivity: adjustable
CO2 Measurement range: 0-2500 PPM
CO2 Accuracy: +/- 75 PPM
CO2 sensor warm-up time: < 10 minutes
Computer Interface: Optional RS 232 / 9-pin D-sub
Weight: 5 lbs.
Dimensions: 8" x 6.5" x 3.1"
Life Expectancy: > 10 years

Sentinel 3-year warranty.

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