This is an emergency power supply battery pack. Put in 4 AA batteries (not included) and you will get a DC 6V battery pack. When your device runs out of power and cannot start, you can connect it as an external battery and access the device normally. The voltage and current are stable and will not damage the device, please feel free to use it. It comes with 6 different output cables, Type-C, 2.5mm Male Plug, USB Mini-B, 3.5mm Male Plug, USB Micro-B, 3.5*1.35mm DC Adapter. It also comes with a strong adhesive to help you fix the battery pack. Ideal for electronic safes, fingerprint safes, electronic locks, gun safe,key safe, LED Lights, etc.