During the day, these energy-efficient Atlantic Solars™ lights harness sunlight energy to charge their internal Lithium Battery. At night they automatically turn on, emitting a bright glow for your fence post line. Each Atlantic Solars™ light is made of Premium Heat-Resistant Plastic for years of use. With our Newest & Improved Solar Panels, a 3.2V Lithium Battery, and 5 Ultra Bright LEDs, its output is virtually unparalleled. Its newest Solar Panels ensure longer illumination (up to 6-10 hours), while the 5 LEDs and 3.2V Battery brighten the light output by 13.3x! • Atlantic Solars™ 5″x 5″ Fence Post Cap Solar Light • One Pre-Installed 3.2V Lithium-Ion Battery • LED: 5 Ultra Bright LEDs, • Solar panel:New & Improved For Superior Charging • Material: Premium Heat-Resistant Plastic • Operating Time: Up to 6-10 hours • Safe & Weather Resistant • Dimensions : 5″ (L) X 5″ (W) X 4″ (H) • Universal post caps – designed to fit on 5 x 5 Vinyl/PVC or Wood Posts • One 5 x 5 Combination Mounting Base for 5 x 5 model has two sides and thus serves two functions. Inside diameter of one side is 4.75″ x 4.75″ (good for wood posts) and inside diameter of other side is 5 1/16″ x 5 1/16″ (good for PVC posts)