When the power suddenly cuts out, this emergency bulb will still light up. In usual use, it works as a normal bulb, turning on or off by wall switch, while the battery charges until full, ready for emergency situations. Suitable for house living, corridors, basements, garages, warehouses, etc. It generates very low heat, saves light power, and is energy-saving and environmentally friendly. Working instructions: 1) When electricity is on, use it like a normal bulb, it will charge for 3-5 hours until full. 2) When electricity is off, use it as an emergency bulb. Power: 7W/12W/15W. Includes 1 x Light Bulb.