First Alert GCO1CN Combination Explosive Gas and Carbon Monoxide Alarm with Backlit Digital Display N/A Imported Versatile CO alarm senses high levels of propane, natural/methane gas, and carbon monoxide Crisp backlit digital display allows you to view current and peak levels Can be remotely muted using almost any household remote control Plugs into any AC outlet for easy setup; backup battery powers unit in case of power outage Loud 85-decibel alarm can be heard easily Plug-in combination carbon monoxide and explosive gas alarm with battery back-up 3-way protection against natural, methane, and propane gases and carbon monoxide Uses electrochemical carbon monoxide sensor--the most accurate technology available Test button and low battery warning Includes 9-volt battery