The CO and NO2 Series transmitters monitor carbon monoxide, or nitrogen dioxide, and are designed for the continuous monitoring of vehicle exhaust in non-hazardous areas. A wide spectrum, long life electrochemical sensor measures the amount of carbon monoxide or nitrogen dioxide in the environment. Both the Room and Duct transmitters are offered in a standard NEMA 1 rated ABS Polycarbonate plastic enclosure. An optional NEMA 4X watertight and dust proof enclosure is available with the room transmitter. Other options include an LCD display with (2) SPDT Form 1C relays and a buzzer.