The Macurco CM-12 is a line voltage, dual relay Carbon Monoxide (CO) detector, controller and transducer. The CM-12 utilizes an internal switching power supply that is capable of using line voltage between 100 and 240VAC and 50-60Hz. The CM-12 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-12 is a low-level meter capable of displaying from 0-200 ppm (parts per million) of Carbon monoxide. The CM-12 is factory calibrated and 100% tested for proper operation, but can also be calibrated in the field.