Carbon monoxide (CO) is a dangerous, colorless and odorless gas that cannot be perceived by humans. CO detectors are required when using carbon monoxide relevant equipment, such as fireplace, gas stove, gas boiler, oil, wood or tiled stove and attached garage. Alarms in case of increased carbon monoxide content in the room air. The LC display is illuminated in blue to indicate the CO concentration. Automatic self-test function. Permanent monitoring and high measuring accuracy.