The CDD4 Series CO2 monitor uses a highly accurate and reliable Non-dispersive Infrared (NDIR) with state-of-the-art digital linearization and temperature compensated circuitry in an attractive, low profile enclosure for room applications and a duct mount version to detect CO2 levels and provides a linear analog signal output of 4-20 mA, 0-5 or 0-10 Vdc signals. The CDD4 is available with ranges of 0-2000 ppm or 0-20,000 ppm (Dual-channel). Parameters are set up via the LCD display which can be provided as viewable or concealed. Various precision thermistors or RTD’s are also available to as an optional output.