Ultra-Sensitive CO Monitor Battery Operated Digital Display DetectorThe Kidde KN COU B is a carbon monoxide monitor that indicates to the presence of low CO levels. Like smoke and CO alarms, this CO monitor samples the air in your home and sounds a loud alarm to warn you of life threatening conditions. In addition, this monitor will indicate low levels of CO (below 30 PPM) which may have health implications if you suffer from certain pre existing health or medical conditions. Detects low levels of carbon monoxide