DIY,EASY TO ALARM AND INSTALL,LOWEST COST BUT HIGH QUALTY,CE,ROHS,SASO,FCC,R&TTE,CCC,APPROVAL,EXPORTED ... . When received alarmMessage, it speaks as you spoken. 6. Li-ion rechargeable battery to back up power built-in panel: >36hours. Auto-switch ... panel with one internal siren and li-ion battery backup: working voltage: 9 dcv, 500ma.Panel Size:30x22x70cm,li-ion battery at 500mA/8.4v with ...