The Amerelle LED Slimline power failure lite automatically lights up when the power fails. It can also be used as a 24 hr guidelight or a handheld flashlight, simply unplug and the light goes on. It has a retractable plug and a built-in NiMH battery recharges when plugged into the outlet. Amerelle LED Slimline power failure lights a necessity for blackouts, storms, natural disasters and tripped breakers.