Solar Post Light
Solar post lights are caps that you install on the end of fence post, decks, or you can even purchase them on stakes so you can line your walkways.
They have a solar panel on the top so that they can capture the sunlight and use it to charge the batteries. When the sun sets, the lights will turn on. LEDs (Led Emitting Diodes) are widely used; LEDs consume very few power, allowing solar lights to stay lit all night long.