The SF450EN from Honeywell is a self-contained Carbon Monoxide alarm, a robust, high-quality device designed for use in all domestic environments such as homes, caravans or boats. It uses the latest electrochemical cell technology to ensure complete accuracy and reliability. The unit is officially approved and Kite marked to the stringent performance requirements of EN50291:2001 the European Standard for domestic Carbon Monoxide alarms. A toxic gas that is difficult to detect, Carbon Monoxide (CO) is often referred to as the Silent Killer. Even with the extensive media attention, it still poisons adults and children. Fossil fuel burning appliances (gas, coal, oil, wood, paraffin etc) create a potential hazard for releasing dangerous levels of CO.