External battery pack with 2.5mm jack is only available for some safes and key safes with external battery power. If the battery fails, the safe can be accessed via a biometric safe by plugging this backup power supply into a module on the safe. It is made of plastic with stable characteristics, high reliability, not easy to damage. It holds four AA-sized standard alkaline or rechargeable batteries. The safe box emergency battery is professional designs, great compatibility and high reliabilitye, ensuring optimal performance and functionality. Material Plastic Specification 2.5mm Interface Type Battery Box Brand Unbranded/Generic MPN MEM94670997649 EAN 4894670997649 .
eBay