FEATURES--Never have a moment of darkness during an unexpected power outage.-Syska's emergency LED bulb automatically switches on when the power goes out.-Exclusively made for emergencies, this innovative bulb looks like any other normal bulb and offers a backup time of up to 3.5 hours.-Automatic On-When there is a power failure, this bulb continues to work by drawing power from its inbuilt battery.-It functions like a regular bulb, just make sure you use the bulb often to recharge its battery.