This alarm plugs into standard outlets without any additional mounting. Plug-in cord offers multiple placement options. Battery operated backup ensures alarm works even during power outages. Digital display illuminates hazard level when in alarm or when any button is pressed.Peak level feature displays the highest concentration of carbon monoxide measured since the unit was last reset. Single button also tests alarm functions. Utilizes electrochemical sensor for increased accuracy. 7-year limited warranty. Meets UL standards.