Universal 5w to 20w LED Emergency Pack 4000mAh
The LTEM40 emergency pack charges when AC power is present.
When fully charged, the circuit will protect the battery from over-charging and the emergency pack will enter stand-by mode. As soon as the AC power fails the battery will supply power to the LED lights.
It can be used in public places to ensure LED lights work normally when mains power fails suddenly because of fire, earthquake, etc.