Black smart panel,cool design,strong function,two way alarm,detector failure report,strong voice prompt,unique design for ... control panel to have a warning of replacing battery.12) Backup Battery: automatically change to battery in support if AC is shut off ... installation.SPEICIFICATIONMain system:1) Power supply: 9V 2) Back up LI-ionbattery: DC10V 1700mA3) Static currency: 65mA 4)Sound index: 110db ...