The Kidde 900-0113 (Model KN-COEG-3) is a 120V AC powered, plug-in carbon monoxide, propane and natural gas alarm with battery backup and a digital display. The 900-0113 is an easy to install unit that provides reliable protection against the dangers of carbon monoxide. The gas sensor is a metal oxide sensor designed to detect natural gas (methane) or propane. The 900-0113 will detect and store measured data of concentrated CO levels as low as 11 and up to 999 PPM with its peak level memory display and will also display ''GAS'' if it has detected natural gas or propane. This alarm gives you several mounting options, including: direct-plug, a 6 ft power cord or table top.