The Macurco CM-xx is a dual relay Carbon Monoxide (CO) detector, controller, and transducer. Available in both a low voltage (CM-6) and line voltage (CM-12) option. The CM-xx has selectable 4-20 mA output, buzzer and digital display options. It is an electronic detection system used to measure the concentration of Carbon Monoxide and provide feedback and automatic exhaust fan control to help reduce CO concentrations in parking garages, maintenance facilities or other commercial applications. The CM-xx is a low-level meter capable of displaying in the range 0-200 ppm (parts per million) of Carbon monoxide. The CM-xx is factory calibrated and 100% tested for proper operation but can also be calibrated in the field.