Solar Fence Post Cap Light with Plastic Lens 4 Lumen - Features durable plastic construction with a black coat finish. During the day the solar panel charges the battery creating electrical power. At dusk, the solar panel, sensing the absence of light, turns on the solar garden light using the electricity stored during the day. The more sunlight the fixture gets, the stronger the charge will be and the longer your fixture will illuminate at night. The solar panel should receive 8 Hours of sunlight for optimum performance. Mounting hardware is included.