Samlex BBM-1225 Battery Backup Module, Converts External Power Supply (12 or 24VDC output) to provide battery charging and un-interrupted backup DC power Converts External Power Supply (12 or 24VDC output) to provide battery charging and un-interrupted backup DC power Instantaneous transfer of DC load from External Power Supply to External Backup Battery and vice versa Suitable for 12V or 24V Lead Acid Battery Systems