ER34615M-T1 Battery. Delivering 3.6V/14.5AH of power, it is a drop in replacement for your WT4911BATT. This will fit and operate the DSC Alexor WT4911B and WT4911R Door Alarm Siren & Strobe.
PLEASE VIEW THE CONNECTOR CLOSELY PRIOR TO PURCHASING - THERE ARE TWO BATTERIES WITH VERY SIMILAR STYLE CONNECTORS FOR DOOR ALARMS. MAKE SURE YOU PURCHASE THE CORRECT ONE.