The GD-888 Series of portable and wall-mounted,Infrared Carbon Dioxide Gas analyzersare available from as low as 0-9990 ppm up to 0-100.0% full scale. Electrochemical oxygen and toxic gas sensors can also be added inline with the built-in air pump. Most units come with backlit LCD display, adjustable alarm, 0-1 VDC output, and rechargeable batteries that allow for portable use or continuously on AC power with the battery charger. CEA Instruments Inc.,, (888) 893-9640.